485BPOS

As filed with the Securities and Exchange Commission on May 21, 2015

Securities Act Registration No. 33-83548

Investment Company Act File No. 811-08748

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

Post-Effective Amendment No. 36

and

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940

Amendment No. 37

WANGER ADVISORS TRUST

(Registrant)

227 West Monroe Street, Suite 3000

Chicago, Illinois 60606

Telephone number: 312.634.9200

Scott R. Plummer c/o Columbia Management Investment Advisers, LLC 225 Franklin Street Boston, MA 02110	P. Zachary Egan     Wanger Advisors Trust     227 West Monroe Street,     Suite 3000     Chicago, Illinois 60606	Mary C. Moynihan Perkins Coie LLP 700 13th Street, N.W., Suite 600 Washington, D.C. 20005
	(Agents for service)

It is proposed that this filing will become effective:

x   immediately upon filing pursuant to rule 485(b)

¨   on              pursuant to rule 485(b)

¨   60 days after filing pursuant to rule 485(a)(1)

¨   on              pursuant to rule 485(a)(1)

¨   75 days after filing pursuant to rule 485(a)(2)

¨   on              pursuant to rule 485(a)(2)

SIGNATURE

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all the requirements for effectiveness of this post-effective amendment pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Chicago and State of Illinois on May 21, 2015.

WANGER ADVISORS TRUST
By:	/s/ P. Zachary Egan
	P. Zachary Egan, President

Pursuant to the requirements of the Securities Act of 1933, this amendment to the registration statement has been signed below by the following persons in the capacities and on the dates indicated.

Name	Title		Date
/s/ Laura M. Born	Trustee and Chair	)
Laura M. Born		)
		)
/s/ Maureen M. Culhane	Trustee	)
Maureen M. Culhane		)
		)
/s/ Margaret M. Eisen	Trustee	)
Margaret M. Eisen		)
		)
/s/ Thomas M. Goldstein	Trustee	)
Thomas M. Goldstein		)
		)
/s/ John C. Heaton	Trustee	)
John C. Heaton		)
		)
/s/ Steven N. Kaplan	Trustee	)
Steven N. Kaplan		)	May 21, 2015
		)
/s/ Charles R. Phillips	Trustee	)
Charles R. Phillips		)
		)
/s/ David J. Rudis	Trustee	)
David J. Rudis		)
		)
/s/ P. Zachary Egan P. Zachary Egan	Trustee and President (principal executive officer)	)
		)
		)
/s/ John M. Kunka	Treasurer (principal financial and accounting officer)	)
John M. Kunka		)

Index of Exhibits Filed with this Amendment

Exhibit No.	Description
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

XML

Wanger Select

SUMMARY OF THE FUND

Investment Objective

Wanger Select (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Wanger Select
Management fees	0.80%
Distribution and/or service (12b-1) fees	none
Other expenses	0.13%
Total annual Fund operating expenses	0.93%

Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

• you invest $10,000 in the Fund for the periods indicated,

• your investment has a 5% return each year, and

• the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown.

Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Expense Example (USD $)	1 year	3 years	5 years	10 years
Wanger Select	95	296	515	1,143

Expense Example, No Redemption (USD $)	1 year	3 years	5 years	10 years
Wanger Select	95	296	515	1,143

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 18% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of companies with market capitalizations under $20 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $20 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $20 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $20 billion at the time of initial investment.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $20 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Colombia).

The Fund invests in a limited number of companies (generally between 30-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers may take advantage of the research and stock-picking capabilities of the Investment Manager to select investments that are “best ideas,” but need not do so and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the most growth potential.

The Investment Manager typically seeks companies with:

• A strong business franchise that offers growth potential.

• Products and services in which the company has a competitive advantage.

• A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Fund may also invest in companies that the Investment Manager believes have good operational fundamentals but that the Investment Manager believes are undervalued due to negative investor sentiment related to company-specific or market-related conditions. Investments in turnaround and development stage companies may also be made when the Investment Manager believes potential returns outweigh risks of losses.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down.

Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives.

Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors.

Opportunistic Investing Risk. Undervalued securities involve the risk that they may never reach their expected full market value, either because the market fails to recognize the security's intrinsic worth or the expected value was misgauged. Undervalued securities also may decline in price even though the Investment Manager believes they are already undervalued. Turnaround companies may never improve their fundamentals, may take much longer than expected to improve, or may improve much less than expected. Development stage companies could fail to develop and deplete their assets, resulting in large percentage losses.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility.

Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including the political, regulatory, economic, social, diplomatic and other conditions or events occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. The performance of the Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations.

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not be traded and are subject to a higher risk of currency devaluations.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights.

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, it may be subject to the liquidity and trading volume risks associated with international investing. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. As a result of significant and sustained reductions in emerging and developed international market trading volumes in the wake of the 2007-2009 financial crisis, it may take longer to buy or sell these securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size, these considerations take on increasing significance and may adversely impact performance.

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the S&P MidCap 400^® Index, the Fund’s primary benchmark and the S&P 500^® Index. The S&P MidCap 400^® Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S. companies. The S&P 500^® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. Although the Fund typically invests in companies with market capitalizations under $20 billion at the time of investment, the comparison to the S&P 500^® Index is presented to show performance against a widely recognized market index.

The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.

The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).

Year by Year Total Return (%)
as of December 31 Each Year

Best and Worst Quarterly Returns
During the Period Shown in the Bar Chart

Best                                                         2nd Quarter 2009                                                         27.72%
Worst                                                      4th Quarter 2008                                                         -29.52%

Average Annual Total Returns (for periods ended December 31, 2014)

Average Annual Total Returns	Inception Date	1 Year	5 Years	10 Years
Wanger Select	Feb. 01, 1999	3.17%	11.37%	7.70%
Wanger Select S&P MidCap 400® Index (reflects no deductions for fees, expenses or taxes)		9.77%	16.54%	9.71%
Wanger Select S&P 500® Index (reflects no deductions for fees, expenses or taxes)		13.69%	15.45%	7.67%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	WANGER ADVISORS TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2015
Wanger International Select
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY OF THE FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Wanger International Select (the Fund) seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 61% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	61.00%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than “Total Net Expenses” shown in the Financial Highlights section of this prospectus because “Total Net Expenses” do not include acquired fund fees and expenses.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that: you invest $10,000 in the Fund for the periods indicated, your investment has a 5% return each year, and the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above. The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom). The Fund also may invest up to 35% of its total assets in companies in emerging markets (for example, China, India and Brazil). The Fund generally invests in at least three countries other than the United States but may invest up to 25% of its total assets in securities of U.S. issuers. Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $25 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $25 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $25 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $25 billion at the time of initial investment. Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $25 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies. The Fund invests in a limited number of foreign companies (generally between 40-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers will take advantage of the research and stock-picking capabilities of the Investment Manager and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the best investment return potential. The Investment Manager typically seeks companies with: A strong business franchise that offers growth potential. Products and services in which the company has a competitive advantage. A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives. Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility. Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest. Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. As a result of significant and sustained reductions in emerging and developed international market trading volumes in the wake of the 2007-2009 financial crisis, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size, these considerations take on increasing significance and may adversely impact performance. Real Estate-Related Investment Risk. Investments in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subject the Fund to, among other things, risks similar to those of direct investments in real estate and the real estate industry in general. These include risks related to general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. REITs are entities that either own properties or make construction or mortgage loans, and also may include operating or finance companies. The value of interests in a REIT may be affected by, among other factors, changes in the value of the underlying properties owned by the REIT, changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs and similar non-U.S. entities depend upon specialized management skills, may have limited financial resources, may have less trading volume in their securities, and may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended. Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including the political, regulatory, economic, social, diplomatic and other conditions or events occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. The performance of the Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not be traded and are subject to a higher risk of currency devaluations. Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors. Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility. Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.
Risk Lose Money [Text]	rr_RiskLoseMoney	There is no assurance that the Fund will achieve its investment objective and you may lose money.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index, the Fund's primary benchmark and the MSCI Europe, Australasia, Far East (MSCI EAFE) Index (Net). The S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index is a subset of the broad market selected by the index sponsor representing the mid-cap developed markets, excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance . The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did. The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index, the Fund's primary benchmark and the MSCI Europe, Australasia, Far East (MSCI EAFE) Index (Net).
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	The S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index is a subset of the broad market selected by the index sponsor representing the mid-cap developed markets, excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance .
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	888.4.WANGER (888.492.6437)
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Year by Year Total Return (%) as of December 31 Each Year
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best                                                         2nd Quarter 2009                                                         25.12% Worst                                                      3rd Quarter 2008                                                         -26.24%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for periods ended December 31, 2014)
Wanger International Select | Wanger International Select
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.94%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.48%
Acquired fund fees and expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total annual Fund operating expenses	rr_ExpensesOverAssets	1.43%	[1]
1 year	rr_ExpenseExampleYear01	146
3 years	rr_ExpenseExampleYear03	452
5 years	rr_ExpenseExampleYear05	782
10 years	rr_ExpenseExampleYear10	1,713
1 year	rr_ExpenseExampleNoRedemptionYear01	146
3 years	rr_ExpenseExampleNoRedemptionYear03	452
5 years	rr_ExpenseExampleNoRedemptionYear05	782
10 years	rr_ExpenseExampleNoRedemptionYear10	1,713
2005	rr_AnnualReturn2005	16.43%
2006	rr_AnnualReturn2006	36.00%
2007	rr_AnnualReturn2007	21.78%
2008	rr_AnnualReturn2008	(44.35%)
2009	rr_AnnualReturn2009	32.92%
2010	rr_AnnualReturn2010	22.09%
2011	rr_AnnualReturn2011	(10.11%)
2012	rr_AnnualReturn2012	22.00%
2013	rr_AnnualReturn2013	14.04%
2014	rr_AnnualReturn2014	(6.96%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	25.12%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(26.24%)
1 Year	rr_AverageAnnualReturnYear01	(6.96%)
5 Years	rr_AverageAnnualReturnYear05	7.27%
10 Years	rr_AverageAnnualReturnYear10	7.32%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 01, 1999
Wanger International Select | S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index (reflects no deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.10%)
5 Years	rr_AverageAnnualReturnYear05	7.53%
10 Years	rr_AverageAnnualReturnYear10	6.25%
Wanger International Select | MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.90%)
5 Years	rr_AverageAnnualReturnYear05	5.33%
10 Years	rr_AverageAnnualReturnYear10	4.43%

[1] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than “Total Net Expenses” shown in the Financial Highlights section of this prospectus because “Total Net Expenses” do not include acquired fund fees and expenses.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	WANGER ADVISORS TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2015
Document Creation Date	dei_DocumentCreationDate	Apr. 30, 2015

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	WANGER ADVISORS TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2015
Wanger USA
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY OF THE FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Wanger USA (the Fund) seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	14.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that: you invest $10,000 in the Fund for the periods indicated, your investment has a 5% return each year, and the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above. The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount any borrowings for investment purposes) in U.S. companies. Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $5 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $5 billion at the time of initial investment. Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Investment Manager typically seeks companies with: A strong business franchise that offers growth potential. Products and services in which the company has a competitive advantage. A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives. Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility. Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors. Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility.
Risk Lose Money [Text]	rr_RiskLoseMoney	There is no assurance that the Fund will achieve its investment objective and you may lose money.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2000 Index, the Fund’s primary benchmark. The Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 10% of the total market capitalization of the Russell 3000 Index. The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did. The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2000 Index, the Fund’s primary benchmark.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	888.4.WANGER (888.492.6437)
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Year by Year Total Return (%) as of December 31 Each Year
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best                                                         3rd Quarter 2009                                                         22.90% Worst                                                      4th Quarter 2008                                                         -27.74%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for periods ended December 31, 2014)
Wanger USA | Wanger USA
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.86%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.10%
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.96%
1 year	rr_ExpenseExampleYear01	98
3 years	rr_ExpenseExampleYear03	306
5 years	rr_ExpenseExampleYear05	531
10 years	rr_ExpenseExampleYear10	1,178
1 year	rr_ExpenseExampleNoRedemptionYear01	98
3 years	rr_ExpenseExampleNoRedemptionYear03	306
5 years	rr_ExpenseExampleNoRedemptionYear05	531
10 years	rr_ExpenseExampleNoRedemptionYear10	1,178
2005	rr_AnnualReturn2005	11.25%
2006	rr_AnnualReturn2006	7.87%
2007	rr_AnnualReturn2007	5.39%
2008	rr_AnnualReturn2008	(39.68%)
2009	rr_AnnualReturn2009	42.23%
2010	rr_AnnualReturn2010	23.35%
2011	rr_AnnualReturn2011	(3.49%)
2012	rr_AnnualReturn2012	20.02%
2013	rr_AnnualReturn2013	33.75%
2014	rr_AnnualReturn2014	4.78%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	22.90%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(27.74%)
1 Year	rr_AverageAnnualReturnYear01	4.78%
5 Years	rr_AverageAnnualReturnYear05	14.90%
10 Years	rr_AverageAnnualReturnYear10	8.07%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 03, 1995
Wanger USA | Russell 2000 Index (reflects no deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.89%
5 Years	rr_AverageAnnualReturnYear05	15.55%
10 Years	rr_AverageAnnualReturnYear10	7.77%

XML

Wanger USA

SUMMARY OF THE FUND

Investment Objective

Wanger USA (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Wanger USA
Management fees	0.86%
Distribution and/or service (12b-1) fees	none
Other expenses	0.10%
Total annual Fund operating expenses	0.96%

Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

• you invest $10,000 in the Fund for the periods indicated,

• your investment has a 5% return each year, and

• the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown.

Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Expense Example (USD $)	1 year	3 years	5 years	10 years
Wanger USA	98	306	531	1,178

Expense Example, No Redemption (USD $)	1 year	3 years	5 years	10 years
Wanger USA	98	306	531	1,178

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount any borrowings for investment purposes) in U.S. companies.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $5 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $5 billion at the time of initial investment.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Investment Manager typically seeks companies with:

• A strong business franchise that offers growth potential.

• Products and services in which the company has a competitive advantage.

• A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives.

Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility.

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2000 Index, the Fund’s primary benchmark. The Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 10% of the total market capitalization of the Russell 3000 Index.

The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.

The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).

Year by Year Total Return (%)
as of December 31 Each Year

Best and Worst Quarterly Returns
During the Period Shown in the Bar Chart

Best                                                         3rd Quarter 2009                                                         22.90%
Worst                                                      4th Quarter 2008                                                         -27.74%

Average Annual Total Returns (for periods ended December 31, 2014)

Average Annual Total Returns	Inception Date	1 Year	5 Years	10 Years
Wanger USA	May 03, 1995	4.78%	14.90%	8.07%
Wanger USA Russell 2000 Index (reflects no deductions for fees, expenses or taxes)		4.89%	15.55%	7.77%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	WANGER ADVISORS TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2015
Wanger International
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY OF THE FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Wanger International (the Fund) seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 28% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	28.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that: you invest $10,000 in the Fund for the periods indicated, your investment has a 5% return each year, and the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above. The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $5 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $5 billion at the time of initial investment. Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Investment Manager typically seeks companies with: A strong business franchise that offers growth potential. Products and services in which the company has a competitive advantage. A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives. Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility. Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including the political, regulatory, economic, social, diplomatic and other conditions or events occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. The performance of the Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not be traded and are subject to a higher risk of currency devaluations. Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. As a result of significant and sustained reductions in emerging and developed international market trading volumes in the wake of the 2007-2009 financial crisis, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size, these considerations take on increasing significance and may adversely impact performance. Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility. Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors.
Risk Lose Money [Text]	rr_RiskLoseMoney	There is no assurance that the Fund will achieve its investment objective and you may lose money.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index, the Fund's primary benchmark and the MSCI Europe, Australasia, Far East (MSCI EAFE) Index (Net). The S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index is a subset of the broad market selected by the index sponsor representing the mid- and small-cap developed and emerging markets, excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance. The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did. The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index, the Fund's primary benchmark and the MSCI Europe, Australasia, Far East (MSCI EAFE) Index (Net).
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	The S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index is a subset of the broad market selected by the index sponsor representing the mid- and small-cap developed and emerging markets, excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	888.4.WANGER (888.492.6437)
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Year by Year Total Return (%) as of December 31 Each Year
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best                                                        2nd Quarter 2009                                                           32.13% Worst                                                     3rd Quarter 2008                                                           -23.14%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for periods ended December 31, 2014)
Wanger International | Wanger International
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.90%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.15%
Total annual Fund operating expenses	rr_ExpensesOverAssets	1.05%
1 year	rr_ExpenseExampleYear01	107
3 years	rr_ExpenseExampleYear03	334
5 years	rr_ExpenseExampleYear05	579
10 years	rr_ExpenseExampleYear10	1,283
1 year	rr_ExpenseExampleNoRedemptionYear01	107
3 years	rr_ExpenseExampleNoRedemptionYear03	334
5 years	rr_ExpenseExampleNoRedemptionYear05	579
10 years	rr_ExpenseExampleNoRedemptionYear10	1,283
2005	rr_AnnualReturn2005	21.53%
2006	rr_AnnualReturn2006	37.16%
2007	rr_AnnualReturn2007	16.31%
2008	rr_AnnualReturn2008	(45.60%)
2009	rr_AnnualReturn2009	49.78%
2010	rr_AnnualReturn2010	24.92%
2011	rr_AnnualReturn2011	(14.62%)
2012	rr_AnnualReturn2012	21.56%
2013	rr_AnnualReturn2013	22.37%
2014	rr_AnnualReturn2014	(4.40%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	32.13%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(23.14%)
1 Year	rr_AverageAnnualReturnYear01	(4.40%)
5 Years	rr_AverageAnnualReturnYear05	8.69%
10 Years	rr_AverageAnnualReturnYear10	9.13%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 03, 1995
Wanger International | S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index (reflects no deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.76%)
5 Years	rr_AverageAnnualReturnYear05	7.14%
10 Years	rr_AverageAnnualReturnYear10	7.65%
Wanger International | MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.90%)
5 Years	rr_AverageAnnualReturnYear05	5.33%
10 Years	rr_AverageAnnualReturnYear10	4.43%

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Dec. 31, 2014
Registrant Name	dei_EntityRegistrantName	WANGER ADVISORS TRUST
Central Index Key	dei_EntityCentralIndexKey	0000929521
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Apr. 30, 2015
Document Effective Date	dei_DocumentEffectiveDate	May 01, 2015
Prospectus Date	rr_ProspectusDate	May 01, 2015

XML

Wanger International Select

SUMMARY OF THE FUND

Investment Objective

Wanger International Select (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses		Wanger International Select
Management fees		0.94%
Distribution and/or service (12b-1) fees		none
Other expenses		0.48%
Acquired fund fees and expenses		0.01%
Total annual Fund operating expenses	[1]	1.43%

Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

• you invest $10,000 in the Fund for the periods indicated,

• your investment has a 5% return each year, and

• the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown.

Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Expense Example (USD $)	1 year	3 years	5 years	10 years
Wanger International Select	146	452	782	1,713

Expense Example, No Redemption (USD $)	1 year	3 years	5 years	10 years
Wanger International Select	146	452	782	1,713

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 61% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom).

The Fund also may invest up to 35% of its total assets in companies in emerging markets (for example, China, India and Brazil). The Fund generally invests in at least three countries other than the United States but may invest up to 25% of its total assets in securities of U.S. issuers.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $25 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $25 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $25 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $25 billion at the time of initial investment.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $25 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies.

The Fund invests in a limited number of foreign companies (generally between 40-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers will take advantage of the research and stock-picking capabilities of the Investment Manager and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the best investment return potential.

The Investment Manager typically seeks companies with:

• A strong business franchise that offers growth potential.

• Products and services in which the company has a competitive advantage.

• A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility.

Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest.

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. As a result of significant and sustained reductions in emerging and developed international market trading volumes in the wake of the 2007-2009 financial crisis, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size, these considerations take on increasing significance and may adversely impact performance.

Real Estate-Related Investment Risk. Investments in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subject the Fund to, among other things, risks similar to those of direct investments in real estate and the real estate industry in general. These include risks related to general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. REITs are entities that either own properties or make construction or mortgage loans, and also may include operating or finance companies. The value of interests in a REIT may be affected by, among other factors, changes in the value of the underlying properties owned by the REIT, changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs and similar non-U.S. entities depend upon specialized management skills, may have limited financial resources, may have less trading volume in their securities, and may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended.

Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including the political, regulatory, economic, social, diplomatic and other conditions or events occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. The performance of the Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations.

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not be traded and are subject to a higher risk of currency devaluations.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors.

Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility.

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the S&P Developed Ex-U.S. Between $2 Billion and $10 Billion^® Index, the Fund's primary benchmark and the MSCI Europe, Australasia, Far East (MSCI EAFE) Index (Net). The S&P Developed Ex-U.S. Between $2 Billion and $10 Billion^® Index is a subset of the broad market selected by the index sponsor representing the mid-cap developed markets, excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance .

The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.

The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).

Year by Year Total Return (%)
as of December 31 Each Year

Best and Worst Quarterly Returns
During the Period Shown in the Bar Chart

Best                                                         2nd Quarter 2009                                                         25.12%
Worst                                                      3rd Quarter 2008                                                         -26.24%

Average Annual Total Returns (for periods ended December 31, 2014)

Average Annual Total Returns	Inception Date	1 Year	5 Years	10 Years
Wanger International Select	Feb. 01, 1999	(6.96%)	7.27%	7.32%
Wanger International Select S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index (reflects no deductions for fees, expenses or taxes)		(2.10%)	7.53%	6.25%
Wanger International Select MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		(4.90%)	5.33%	4.43%

[1] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than “Total Net Expenses” shown in the Financial Highlights section of this prospectus because “Total Net Expenses” do not include acquired fund fees and expenses.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	WANGER ADVISORS TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2015
Wanger Select
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	SUMMARY OF THE FUND
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Wanger Select (the Fund) seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 18% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	18.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that: you invest $10,000 in the Fund for the periods indicated, your investment has a 5% return each year, and the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above. The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Fund invests a majority of its net assets in the common stock of companies with market capitalizations under $20 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $20 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $20 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $20 billion at the time of initial investment. Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $20 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Colombia). The Fund invests in a limited number of companies (generally between 30-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers may take advantage of the research and stock-picking capabilities of the Investment Manager to select investments that are “best ideas,” but need not do so and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the most growth potential. The Investment Manager typically seeks companies with: A strong business franchise that offers growth potential. Products and services in which the company has a competitive advantage. A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. The Fund may also invest in companies that the Investment Manager believes have good operational fundamentals but that the Investment Manager believes are undervalued due to negative investor sentiment related to company-specific or market-related conditions. Investments in turnaround and development stage companies may also be made when the Investment Manager believes potential returns outweigh risks of losses. The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest. Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives. Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility. Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors. Opportunistic Investing Risk. Undervalued securities involve the risk that they may never reach their expected full market value, either because the market fails to recognize the security's intrinsic worth or the expected value was misgauged. Undervalued securities also may decline in price even though the Investment Manager believes they are already undervalued. Turnaround companies may never improve their fundamentals, may take much longer than expected to improve, or may improve much less than expected. Development stage companies could fail to develop and deplete their assets, resulting in large percentage losses. Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility. Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including the political, regulatory, economic, social, diplomatic and other conditions or events occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. The performance of the Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not be traded and are subject to a higher risk of currency devaluations. Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, it may be subject to the liquidity and trading volume risks associated with international investing. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. As a result of significant and sustained reductions in emerging and developed international market trading volumes in the wake of the 2007-2009 financial crisis, it may take longer to buy or sell these securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size, these considerations take on increasing significance and may adversely impact performance. Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.
Risk Lose Money [Text]	rr_RiskLoseMoney	There is no assurance that the Fund will achieve its investment objective and you may lose money.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the S&P MidCap 400® Index, the Fund’s primary benchmark and the S&P 500® Index. The S&P MidCap 400® Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S. companies. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. Although the Fund typically invests in companies with market capitalizations under $20 billion at the time of investment, the comparison to the S&P 500® Index is presented to show performance against a widely recognized market index. The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did. The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the S&P MidCap 400® Index, the Fund’s primary benchmark and the S&P 500® Index.
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	The S&P MidCap 400® Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S. companies. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. Although the Fund typically invests in companies with market capitalizations under $20 billion at the time of investment, the comparison to the S&P 500® Index is presented to show performance against a widely recognized market index.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	888.4.WANGER (888.492.6437)
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance is no guarantee of how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Year by Year Total Return (%) as of December 31 Each Year
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best                                                         2nd Quarter 2009                                                         27.72% Worst                                                      4th Quarter 2008                                                         -29.52%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (for periods ended December 31, 2014)
Wanger Select | Wanger Select
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.80%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses	rr_OtherExpensesOverAssets	0.13%
Total annual Fund operating expenses	rr_ExpensesOverAssets	0.93%
1 year	rr_ExpenseExampleYear01	95
3 years	rr_ExpenseExampleYear03	296
5 years	rr_ExpenseExampleYear05	515
10 years	rr_ExpenseExampleYear10	1,143
1 year	rr_ExpenseExampleNoRedemptionYear01	95
3 years	rr_ExpenseExampleNoRedemptionYear03	296
5 years	rr_ExpenseExampleNoRedemptionYear05	515
10 years	rr_ExpenseExampleNoRedemptionYear10	1,143
2005	rr_AnnualReturn2005	10.49%
2006	rr_AnnualReturn2006	19.70%
2007	rr_AnnualReturn2007	9.39%
2008	rr_AnnualReturn2008	(49.06%)
2009	rr_AnnualReturn2009	66.19%
2010	rr_AnnualReturn2010	26.57%
2011	rr_AnnualReturn2011	(17.68%)
2012	rr_AnnualReturn2012	18.46%
2013	rr_AnnualReturn2013	34.58%
2014	rr_AnnualReturn2014	3.17%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	27.72%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(29.52%)
1 Year	rr_AverageAnnualReturnYear01	3.17%
5 Years	rr_AverageAnnualReturnYear05	11.37%
10 Years	rr_AverageAnnualReturnYear10	7.70%
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 01, 1999
Wanger Select | S&P MidCap 400® Index (reflects no deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	9.77%
5 Years	rr_AverageAnnualReturnYear05	16.54%
10 Years	rr_AverageAnnualReturnYear10	9.71%
Wanger Select | S&P 500® Index (reflects no deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.69%
5 Years	rr_AverageAnnualReturnYear05	15.45%
10 Years	rr_AverageAnnualReturnYear10	7.67%

XML

Wanger International

SUMMARY OF THE FUND

Investment Objective

Wanger International (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay as an investor in the Fund. The table does not reflect any fees or expenses imposed by your Contract or Qualified Plan, which are disclosed in your separate Contract prospectus or Qualified Plan disclosure documents. If the additional fees or expenses were reflected, the expenses set forth below would be higher.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses	Wanger International
Management fees	0.90%
Distribution and/or service (12b-1) fees	none
Other expenses	0.15%
Total annual Fund operating expenses	1.05%

Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

• you invest $10,000 in the Fund for the periods indicated,

• your investment has a 5% return each year, and

• the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

The example does not reflect any fees and expenses that apply to your Contract or Qualified Plan. Inclusion of these charges would increase expenses for all periods shown.

Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Expense Example (USD $)	1 year	3 years	5 years	10 years
Wanger International	107	334	579	1,283

Expense Example, No Redemption (USD $)	1 year	3 years	5 years	10 years
Wanger International	107	334	579	1,283

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 28% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations under $5 billion at the time of initial investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Under normal circumstances, the Fund may invest in companies with market capitalizations above $5 billion at the time of initial investment, provided that immediately after that investment a majority of its net assets would be invested in companies whose market capitalizations were under $5 billion at the time of initial investment.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Investment Manager typically seeks companies with:

• A strong business franchise that offers growth potential.

• Products and services in which the company has a competitive advantage.

• A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risk, including those described below. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Market Risk. Market risk refers to the possibility that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. An investment in the Fund could lose money over short or long periods. Although equity securities generally tend to have greater price volatility than debt securities, under certain market conditions, debt securities may have comparable or greater price volatility.

Foreign Securities Risk. Investments in or exposure to foreign securities involve certain risks not associated with investments in or exposure to securities of U.S. companies. Foreign securities subject the Fund to the risks associated with investing in the particular country of an issuer, including the political, regulatory, economic, social, diplomatic and other conditions or events occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. The performance of the Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations.

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not be traded and are subject to a higher risk of currency devaluations.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights.

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. As a result of significant and sustained reductions in emerging and developed international market trading volumes in the wake of the 2007-2009 financial crisis, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size, these considerations take on increasing significance and may adversely impact performance.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly. Generally, the more the Fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility.

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which would negatively affect the Fund’s performance. Poor performance may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters or other events, conditions or factors.

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the S&P Global Ex-U.S. Between $500 Million and $5 Billion^® Index, the Fund's primary benchmark and the MSCI Europe, Australasia, Far East (MSCI EAFE) Index (Net). The S&P Global Ex-U.S. Between $500 Million and $5 Billion^® Index is a subset of the broad market selected by the index sponsor representing the mid- and small-cap developed and emerging markets, excluding the United States. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance.

The returns shown do not reflect any fees and expenses imposed under your Contract or Qualified Plan and would be lower if they did.

The Fund’s past performance is no guarantee of how the Fund will perform in the future. Daily and month-end performance information is available by calling the Investment Manager at 888.4.WANGER (888.492.6437).

Year by Year Total Return (%)
as of December 31 Each Year

Best and Worst Quarterly Returns
During the Period Shown in the Bar Chart

Best                                                        2nd Quarter 2009                                                           32.13%
Worst                                                     3rd Quarter 2008                                                           -23.14%

Average Annual Total Returns (for periods ended December 31, 2014)

Average Annual Total Returns	Inception Date	1 Year	5 Years	10 Years
Wanger International	May 03, 1995	(4.40%)	8.69%	9.13%
Wanger International S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index (reflects no deductions for fees, expenses or taxes)		(1.76%)	7.14%	7.65%
Wanger International MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		(4.90%)	5.33%	4.43%