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Vanguard Mid-Cap Growth Index Fund

Summary Prospectus

April 29, 2010

Investor Shares

Vanguard Mid-Cap Growth Index Fund Investor Shares (VMGIX)

The Fund’s statutory Prospectus and Statement of Additional Information dated

April 29, 2010, and financial highlights information from the most recent

shareholder report are incorporated into and made part of this Summary

Prospectus by reference.

Before you invest, you may want to review the Fund’s Prospectus, which

contains more information about the Fund and its risks. You can find

the Fund’s Prospectus and other information about the Fund online at

www.vanguard.com/prospectus. You can also get this information at

no cost by calling 800-662-7447 or by sending an e-mail request to

online@vanguard.com.

The Securities and Exchange Commission has not approved or disapproved these securities or passed

upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Investment Objective

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization growth stocks.

Fees and Expenses

The following tables describe the fees and expenses you may pay if you buy and hold Investor Shares of the Fund.


Shareholder Fees
(Fees paid directly from your investment)
Sales Charge (Load) Imposed on Purchases	None
Purchase Fee	None¹
Sales Charge (Load) Imposed on Reinvested Dividends	None
Redemption Fee	None
Account Service Fee (for fund account balances below $10,000)	$20/year

1 The Fund reserves the right to deduct a purchase fee from future purchases of shares.

Annual Fund Operating Expenses

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


Management Expenses	0.24%
12b-1 Distribution Fee	None
Other Expenses	0.06%
Total Annual Fund Operating Expenses	0.30%

Example

The following example is intended to help you compare the cost of investing in the Fund’s Investor Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund’s shares. This example assumes that the Shares provide a return of 5% a year and that operating expenses remain the same. The results apply whether or not you redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:


1 Year	3 Years	5 Years	10 Years
$31	$97	$169	$381

Portfolio Turnover

The Fund pays 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 and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 43% of the average value of its portfolio.

Primary Investment Strategies

The Fund employs a “passive management”—or indexing—investment approach designed to track the performance of the MSCI^®US Mid Cap Growth Index, a broadly diversified index of growth stocks of medium-size U.S. companies. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Primary Risks

An investment in the Fund could lose money over short or even long periods. You should expect the Fund’s share price and total return to fluctuate within a wide range, like the fluctuations of the overall stock market. The Fund’s performance could be hurt by:

• Stock market risk, which is the chance that stock prices overall will decline. Stock markets tend to move in cycles, with periods of rising prices and periods of falling prices. The Fund’s target index may, at times, become focused in stocks of a particular sector, category, or group of companies. Because the Fund seeks to track its target index, the Fund may underperform the overall stock market.

• Investment style risk, which is the chance that returns from mid-capitalization growth stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Annual Total Returns

The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the Investor Shares compare with those of the Fund‘s target index. Keep in mind that the Fund’s past

performance (before and after taxes) does not indicate how the Fund will perform in the future. Updated performance information is available on our website at www.vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.

During the periods shown in the bar chart, the highest return for a calendar quarter was 17.99% (quarter ended September 30, 2009), and the lowest return for a quarter was –27.33% (quarter ended December 31, 2008).


Average Annual Total Returns for Periods Ended December 31, 2009
		Since
		Inception
		(Aug. 24,
	1 Year	2006)
Vanguard Mid-Cap Growth Index Fund Investor Shares
Return Before Taxes	42.54%	–0.99%
Return After Taxes on Distributions	42.44	–1.06
Return After Taxes on Distributions and Sale of Fund Shares	27.79	–0.84
MSCI US Mid Cap Growth Index
(reflects no deduction for fees, expenses, or taxes)	43.01%	–0.85%

Actual after-tax returns depend on your tax situation and may differ from those shown in the preceding table. When after-tax returns are calculated, it is assumed that the shareholder was in the highest individual federal marginal income tax bracket at the time of each distribution of income or capital gains or upon redemption. State and local income taxes are not reflected in the calculations. Please note that after-tax returns are not relevant for a shareholder who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan. Also, figures captioned Return After Taxes on Distributions and Sale of Fund Shares will be higher than other figures for the

same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.

Investment Advisor
The Vanguard Group, Inc.

Portfolio Manager

Gerard C. O’Reilly, Principal of Vanguard. He has managed the Fund since its inception in 2006.

Purchase and Sale of Fund Shares

You may purchase or redeem shares online through our website at www.vanguard.com, by mail (The Vanguard Group, P.O. Box 1110, Valley Forge, PA 19482-1110), or by telephone (800-662-2739). The following table provides the Fund’s minimum initial and subsequent investment requirements.


Account Minimums	Investor Shares
To open and maintain an account	$3,000
To add to an existing account	$100 (other than by Automatic Investment Plan,
	which has no established minimum).

Tax Information

The Fund’s distributions may be taxable as ordinary income or capital gain.

Payments to Financial Intermediaries

The Fund and its investment advisor do not pay financial intermediaries for sales of Fund shares or related services.

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Vanguard Mid-Cap Growth Index Fund Investor Shares—Fund Number 832

The Fund or securities referred to herein are not sponsored, endorsed, or promoted by MSCI, and MSCI bears no liability with respect to any such funds or securities. For any such funds or securities, the Statement of Additional Information contains a more detailed description of the limited relationship MSCI has with The Vanguard Group and any related funds.

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