File No. 001-16189

FORM 11-K

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

ANNUAL REPORT

PURSUANT TO SECTION 15(d)

of the

SECURITIES AND EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2005

NORTHERN INDIANA PUBLIC SERVICE COMPANY

BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

NiSource Inc.
801 E. 86th Avenue
Merrillville, IN 46410

Northern Indiana Public
Service Company
Bargaining Unit Tax
Deferred Savings Plan

Financial Statements as of December 31,
2005 and 2004 and for the Year Ended
December 31, 2005, Supplemental
Schedule as of December 31, 2005, and Report
of Independent Registered Public Accounting
Firm

NORTHERN INDIANA PUBLIC SERVICE COMPANY
BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

TABLE OF CONTENTS

	Page
REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM		1
FINANCIAL STATEMENTS:
Statements of Net Assets Available for Benefits as of December 31, 2005 and 2004		2
Statement of Changes in Net Assets Available for Benefits for the year ended December 31, 2005		3
Notes to Financial Statements		4-8
SUPPLEMENTAL SCHEDULE:
Form 5500 Schedule H, Part IV, Line 4i — Schedule of Assets (Held at End of Year) as of December 31, 2005		10

NOTE: Schedules not filed herewith are omitted because of the absence of the conditions under which they are required by the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Administrative Committee of the
Northern Indiana Public Service Company Bargaining Unit Tax Deferred Savings Plan
Merrillville, Indiana

We have audited the accompanying statements of net assets available for benefits of the Northern Indiana Public Service Company Bargaining Unit Tax Deferred Savings Plan (the “Plan”) as of December 31, 2005 and 2004, and the related statement of changes in net assets available for benefits for the year ended December 31, 2005. These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. The Plan is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Plan’s internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, such financial statements present fairly, in all material respects, the net assets available for benefits of the Plan as of December 31, 2005 and 2004, and the changes in net assets available for benefits for the year ended December 31, 2005, in conformity with accounting principles generally accepted in the United States of America.

Our audits were conducted for the purpose of forming an opinion on the basic financial statements taken as a whole. The supplemental schedule of assets (held at end of year) as of December 31, 2005, is presented for the purpose of additional analysis and is not a required part of the basic financial statements, but is supplementary information required by the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. This schedule is the responsibility of the Plan’s management. Such schedule has been subjected to the auditing procedures applied in our audit of the basic 2005 financial statements and, in our opinion, is fairly stated in all material respects when considered in relation to the basic 2005 financial statements taken as a whole.

/s/ Deloitte & Touche LLP
Indianapolis, Indiana
June 29, 2006

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NORTHERN INDIANA PUBLIC SERVICE COMPANY
BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS
DECEMBER 31, 2005 AND 2004

	2005		2004
ASSETS:
Investments—at fair value:
Mutual funds	$	66,712,012	$	61,809,508
Plan interest in Master Trust		17,853,156		—
Common stock fund		—		19,304,470
Money market funds		10,340,802		9,890,356
Collective trusts		456,619		—
Participant loans		2,384,439		2,038,914
NET ASSETS AVAILABLE FOR BENEFITS	$	97,747,028	$	93,043,248

See accompanying notes to financial statements.

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NORTHERN INDIANA PUBLIC SERVICE COMPANY
BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS
YEAR ENDED DECEMBER 31, 2005

ADDITIONS:
Contributions:
Participant	$	6,120,072
Employer		926,148
Total contributions		7,046,220
Investment income (loss):
Net appreciation in fair value of investments		38,260
Dividends and interest		4,228,326
Interest in losses of Master Trust		(823,040	)
Investment income, net		3,443,546
Total additions		10,489,766
DEDUCTIONS:
Benefits paid to participants		(5,631,234	)
Administrative expenses		(2,441	)
Transfers—net		(152,311	)
Total deductions		(5,785,986	)
NET INCREASE		4,703,780
NET ASSETS AVAILABLE FOR BENEFITS—Beginning of year		93,043,248
NET ASSETS AVAILABLE FOR BENEFITS—End of year	$	97,747,028

See accompanying notes to financial statements.

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NORTHERN INDIANA PUBLIC SERVICE COMPANY
BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

NOTES TO FINANCIAL STATEMENTS

1.	DESCRIPTION OF PLAN
	Northern Indiana Public Service Company (the “Company” or “NIPSCO”) is a wholly owned subsidiary of NiSource Inc. The following description of the Northern Indiana Public Service Company Bargaining Unit Tax Deferred Savings Plan (the “Plan”) provides general information regarding the Plan. Participants should refer to the Plan document for a more complete description of the Plan’s provisions.
	General—The Plan was established effective October 1, 1987. It is a defined contribution plan available to substantially all active bargaining unit employees of the Company. It is subject to the provisions of the Employee Retirement Income Security Act of 1974 (“ERISA”), as amended.
	Plan Administration—The Company serves as administrator and sponsor of the Plan. NiSource Inc. maintains an administrative committee appointed by the Board of Directors, which has the responsibility to assist the Company in administering the Plan. Fidelity Management Trust Company (the “Trustee”) holds all of the Plan’s assets and executes all investment transactions.
	Contributions—Each year, participants may contribute up to 50% of compensation (as defined in the Plan) on a pre-tax basis and 25% on an after-tax basis, up to 75% in total. Additionally, participants who are at least 50 years old can make catch-up contributions to the Plan. Contributions are subject to certain limitations. Participants direct the investment of their contributions into various investment options offered by the Plan. The Plan currently offers twenty-seven mutual funds, two money market funds and collective trust and one common stock fund held in a Master Trust as investment options for participants. Effective January 1, 2005, four of the twenty-seven mutual funds were closed to new investment.
	The Company contributes an amount equal to 1/9th of a participant’s pre-tax contribution. The matching contribution is invested directly into the Plan interest in the Master Trust. Employees may subsequently redirect matching contributions among any of the funds available in the Plan.
	Beginning January 1, 2005, all NIPSCO active union employees are given a choice between a Cash Balance and Final Average Pay defined benefit plan. Effective June 1, 2005, for employees who choose the Cash Balance defined benefit plan, the Company contributes an amount equal to 75% of the first 6% of the participants’ combined pre-tax and post-tax contributions. The Company match remains the same, as listed in the preceding paragraph, for employees who choose the Final Average Pay plan.
	Rollovers from Other Qualified Employer Plans—The Plan allows for employees to transfer certain of their other qualified employer retirement plan assets to the Plan. These amounts are reflected in participant contributions in the accompanying statement of changes in net assets available for benefits.
	Participant Accounts—Each participant’s account is credited with the participant’s contribution and allocations of the Company’s contribution and Plan earnings and charged with an allocation of Plan losses and certain administrative expenses.
	Vesting—Participants are fully vested in their accounts at all times.

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Participant Loans—Participants that have participated in the Plan for at least one year may borrow up to 50% from their accounts a minimum of $1,000 up to a maximum of $50,000. The loans are secured by the balance in the participant’s account and bear interest at prime rate plus 1% based on the last day of the month prior to loan initiation. Interest rates on outstanding loans range from 4.75% to 9.5% at December 31, 2005. Principal and interest are paid ratably through payroll deductions over a period not to exceed five years, unless the loan is to purchase the participant’s primary residence which allows repayment up to 15 years (30 years prior to January 1, 2002). Participants may have two loans outstanding at any given time.

Participant Withdrawals—Withdrawals from the Plan are generally permitted when the participant terminates employment, retires, or becomes permanently disabled. The Plan offers the following options for withdrawals while still employed:

• Age 59¹/2 withdrawals;

• Voluntary withdrawals from after-tax, rollover and matching contributions; and

• Hardship withdrawals, subject to the Plan rules.

A Company matching contribution or hardship withdrawal may result in the suspension of the participant’s deferral and Company matching contributions for six months.

Payment of Benefits—All amounts distributed from a participant’s account following termination of employment shall be distributed in one lump-sum amount, in cash. If the amount payable under the plan to any participant or beneficiary is less than or equal to $5,000, the administrative committee will direct that such amount be paid in a lump sum.

Transfers Between Plans—Transfers between plans occur when employees transfer in/out of a union but stay with NiSource Inc., which results in a transfer of any related balances between this Plan and other plans. Amounts are included in transfers, net on the accompanying statement of changes in net assets available for benefits.

2.	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Basis of Accounting—The financial statements of the Plan were prepared in accordance with accounting principles generally accepted in the United States of America using the accrual basis of accounting.
	Use of Estimates—The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and changes therein, and disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
	Investment Valuation and Income Recognition—The Plan’s investments are stated at fair value. Quoted market prices are used to value investments. The fair value of the collective trusts is based on quoted redemption values as of the last day of the Plan year. The Plan’s investment in the Master Trust (see Note 6) is presented at fair value, which has been determined based on the fair value of the underlying investments of the Master Trust. Participant loans are valued at cost, which approximates fair value. Purchases and sales of securities are recorded on a trade-date basis. Dividends are recorded on the record date.
	Payment of Benefits—Benefits are recorded when paid.

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Administrative Expenses—Most administrative expenses of the Plan are paid by the Company. Certain other expenses of the Plan such as investment manager and broker fees are paid by the Plan. Certain loan administration fees are paid from the individual participant accounts.

3.	INVESTMENTS
	The following presents investments that represent 5% or more of the Plan’s net assets:

	December 31
	2005		2004
Fidelity Magellan Fund	$	25,295,761	$	26,757,822
Fidelity Growth and Income Fund		13,726,922		14,804,291
Fidelity Retirement Money Market Fund		9,884,183		9,890,356
Fidelity Intermediate Bond Fund		5,889,355		6,162,387
* Plan interest in Master Trust		17,853,156		—
* Nisource Inc. Common Stock Fund		—		19,304,470

* Includes nonparticipant-directed and participant-directed investments

During 2005, the Plan’s mutual fund investments (including gains and losses on investments bought and sold, as well as held during the year) appreciated in value by $38,260.

The Plan provides for investments in mutual funds and common stock that, in general, are exposed to various risks, such as interest rate, credit and overall market volatility risks. Due to the level of risk associated with certain investment securities, it is reasonably possible that changes in the values of investment securities will occur in the near term and that such changes could materially affect the amounts reported in the accompanying statements of net assets available for benefits.

4.	RELATED-PARTY TRANSACTIONS
	Certain Plan investments are shares of mutual funds managed by the Fidelity Management Trust Company. Fidelity Management Trust Company is the Trustee, as defined by the Plan; therefore, these transactions qualify as party-in-interest transactions. See Note 6 for additional related party information.

5.	PLAN TERMINATION
	Although it has not expressed any intention to do so, the Company reserves the right under the Plan document to terminate the Plan at any time, subject to the provisions of ERISA. In the event of Plan termination, the rights of each participant to all amounts then credited to the participant’s account will continue to be nonforfeitable.

6.

INTEREST IN MASTER TRUST

Description of the Master Trust—The Master Trust was established for the investment of assets of the Plan and several other NiSource Inc. sponsored defined contribution retirement plans. Each participating retirement plan has an undivided interest in the Master Trust. The assets and liabilities of the Master Trust are held by the Trustee. At December 31, 2005, the Plan’s interest in the net assets of the Master Trust was approximately 12%. Investment income (losses) and certain administrative expenses relating to the Master Trust are allocated to the individual plans based upon average daily balances invested by each plan.

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Summary of Significant Accounting Policies

Valuation of Investments—The Master Trust consists solely of investment in the NiSource Inc. Common Stock Fund, which is stated at fair value, measured by quoted market price in an active market.

Employee Stock Ownership Plan—The NiSource Inc. Common Stock Fund operates as an Employee Stock Ownership Plan (“ESOP”). As an ESOP, under the terms of this plan, participants may diversify their investment attributable to employer match at any time. Participants may also elect to have dividends paid to them in cash or reinvested in the fund.

Voting and Tendering Rights of NiSource Inc. Common Stock Fund Participants—Each participant in the NiSource Inc. Common Stock Fund is entitled to direct the Trustee as to the manner of voting at each meeting of shareholders. A participant’s interest is represented by the value of the participant’s interest in the NiSource Inc. Common Stock Fund.

Payment of Benefits—Any distribution consisting of units in the Plan interest in the Master Trust may be paid in cash or in whole shares of common stock represented by such units plus a cash amount equal to the fair market value of any fraction of a share of the common stock fund.

Other—Purchases and sales of stock held in the Master Trust are reflected as of the trade date. Pending sales and purchases of investments of the Master Trust include receivables and payables, respectively, related to transactions that have not been settled at year-end.

Dividend income on stock held in the Master Trust is recorded on the ex-dividend date. Interest earned in the Master Trust is recorded on the accrual basis.

Net appreciation (depreciation) in the fair value of investments held by the Master Trust include unrealized gains and losses associated with changes in the fair values of assets held at year-end as well as realized gains and losses on investments that were sold during the year.

Investments in the NiSource Inc. Common Stock Fund are exposed to various risks such as interest rate, credit and overall market volatility crisis. Due to the level of risk associated with the investment securities, it is reasonably possible that changes in the values of investment securities will occur in the near term and that such changes could materially affect the amounts reported in the accompanying statements of net assets available for benefits.

Related Party Transactions—The Master Trust invests in shares of the NiSource Inc. Common Stock Fund, which is managed by the Trustee that holds the assets of the Master Trust, and therefore, these transactions qualify as party-in-interest transactions.

The net assets of the Master Trust consist of investments at a fair value of $147,587,948 as of December 31, 2005.

Investment income (loss) for the Master Trust is as follows for the year ended December 31, 2005:

Net appreciation (depreciation) in fair value of investments	$	(13,310,998	)
Interest and dividends		6,538,137
Investment loss, net	$	(6,772,861	)

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7.

TAX STATUS

The Internal Revenue Service (the “IRS”) has issued a determination letter dated September 26, 2003, stating that the Plan is qualified under applicable sections of the Internal Revenue Code (the “IRC”). The Plan has been amended since receiving the determination letter. However, the Plan administrator believes that the Plan is designed and is currently being operated in compliance with the applicable requirements of the IRC.

******

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SUPPLEMENTAL SCHEDULE

NORTHERN INDIANA PUBLIC SERVICE COMPANY
BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

FORM 5500 SCHEDULE H, PART IV, LINE 4i—
EIN: 35-2108964, PLAN 005
SCHEDULE OF ASSETS (HELD AT END OF YEAR)
DECEMBER 31, 2005

	Identity of Issuer,	Description of Investment,
	Borrower, Lessor,	Including Maturity Date, Rate of Interest,			Fair
	or Similar Party	Collateral and Par or Maturity Value	Cost **		Value
*	NiSource Inc.	Plan interest in Master Trust	$	16,301,478	$	17,853,156
*	Fidelity Investments	Retirement Money Market Fund				9,884,183
*	Fidelity Investments	Managed Income Portfolio				456,619
*	Fidelity Investments	Magellan Fund				25,295,761
*	Fidelity Investments	Contrafund				3,569,645
*	Fidelity Investments	Equity Income Fund				875,101
*	Fidelity Investments	Growth Fund				1,064,651
*	Fidelity Investments	Growth and Income Fund				13,726,922
*	Fidelity Investments	Intermediate Bond Fund				5,889,355
*	Fidelity Investments	Overseas Fund				1,893,820
*	Fidelity Investments	Europe Fund				151,439
*	Fidelity Investments	Pacific Basin Fund				119,030
*	Fidelity Investments	Balanced Fund				2,098,889
*	Fidelity Investments	Puritan Fund				875,867
*	Fidelity Investments	Small Cap Independent Fund				1,213,868
*	Fidelity Investments	Spartan U.S. Equity Index Fund				2,014,117
*	Fidelity Investments	Freedom Income Fund				336,855
*	Fidelity Investments	Freedom 2010 Fund				1,332,995
*	Fidelity Investments	Freedom 2020 Fund				397,802
*	Fidelity Investments	Freedom 2030 Fund				162,368
*	Fidelity Investments	Freedom 2040 Fund				81,268
	PIMCO Investments	Total Return Fund (institutional)				836,163
	PIMCO Investments	Long-Term Government Fund				681,745
	PIMCO Investments	Low-Duration Fund (institutional)				154,088
	PIMCO Investments	StockPLUS Fund (institutional)				273,722
	Janus investments	SmallCap Value Fund (institutional)				1,644,225
	Dreyfus Investments	Emerging Leaders Fund				386,205
	Morgan Stanley Investments	U.S. SmallCap Core Fund				509,868
	Vanguard Investments	U.S. Growth Investor Shares Fund				157,438
	American Funds Investments	EuroPacific Growth Fund				1,425,424
*	Various Plan participants	Participant loans, with interest rates ranging from 4.75% to 9.5% and maturity dates ranging from January 2006 to October 2031.				2,384,439
	TOTAL ASSETS (HELD AT END OF YEAR)				$	97,747,028

*	Denotes a party-in-interest
**	Cost omitted for participant directed investments

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CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 333-107421 and 333-107421-01 of NiSource Inc. on Form S-3, Registration Statement Nos. 333-127811, 333-127812, 333-107748, and 333-107743 of NiSource Inc. on Form S-8, and Registration Statement Nos. 333-33896 and 333-33896-01 of NiSource Inc. on Form S-4, of our report dated June 29, 2006 , relating to the financial statements of Northern Indiana Public Service Company Bargaining Unit Tax Deferred Savings Plan (the “Plan”), appearing in this Annual Report on Form 11-K of the Plan for the year ended December 31, 2005.

/s/ Deloitte & Touche LLP
Indianapolis, Indiana
June 29, 2006

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the administrative Committee has duly caused this annual report to be signed on its behalf by the undersigned hereunto duly authorized.

NORTHERN INDIANA PUBLIC SERVICE COMPANY
BARGAINING UNIT TAX DEFERRED SAVINGS PLAN

By
	/s/ David J. Vajda
	Vice President & Treasurer, NiSource Inc.
	Member, Administrative Committee

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Each of the undersigned, in his capacity as an officer of NiSource Inc., hereby certifies as required by 18 U.S.C. ss.1350, that, to his knowledge, the accompanying annual report on Form 11-K of the Northern Indiana Public Service Company Bargaining Unit Tax Deferred Savings Plan for the fiscal year ended on December 31, 2005 fully complies with the requirements of 15 U.S.C. ss.78m and that the information contained in the accompanying annual report fairly presents, in all material respects, the net assets of the Plan available for benefits and changes in those net assets.

/s/ Robert C. Skaggs, Jr.	/s/ Michael W. O’Donnell
President and	Executive Vice President and
Chief Executive Officer	Chief Financial Officer

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