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SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 11-K

(Mark One)

For the fiscal year ended December 31, 2008

OR

For the transition period from              to             

Commission file number                     

STATE STREET SALARY SAVINGS PROGRAM

STATE STREET CORPORATION

One Lincoln Street

Boston, Massachusetts 02111

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AUDITED FINANCIAL STATEMENTS

AND SUPPLEMENTAL SCHEDULE

State Street Salary Savings Program

Years Ended December 31, 2008 and 2007

With Report of Independent Registered Public Accounting Firm

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State Street Salary Savings Program

Audited Financial Statements and Supplemental Schedule

Years Ended December 31, 2008 and 2007

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Report of Independent Registered Public Accounting Firm

The North America Regional Benefits Committee and Plan Participants

State Street Salary Savings Program

We have audited the accompanying statements of net assets available for benefits of the State Street Salary Savings Program as of December 31, 2008 and 2007, and the related statements of changes in net assets available for benefits for the years then ended. 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. We were not engaged to perform an audit of the Plan’s 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, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the Plan at December 31, 2008 and 2007, and the changes in its net assets available for benefits for the years then ended, in conformity with U.S. generally accepted accounting principles.

Our audits were performed for the purpose of forming an opinion on the financial statements taken as a whole. The accompanying supplemental schedule of assets (held at end of year) as of December 31, 2008 is presented for purposes of additional analysis and is not a required part of the 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 supplemental schedule is the responsibility of the Plan’s management. The supplemental schedule has been subjected to the auditing procedures applied in our audits of the financial statements and, in our opinion, is fairly stated in all material respects in relation to the financial statements taken as a whole.

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State Street Salary Savings Program

Statements of Net Assets Available for Benefits

See accompanying notes.

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State Street Salary Savings Program

Statements of Changes in Net Assets Available for Benefits

See accompanying notes.

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State Street Salary Savings Program

Notes to Financial Statements

December 31, 2008

1. Description of the Plan

The description of the State Street Salary Savings Program (the Plan) is provided for general information purposes only. Employees should refer to the Summary Plan Description and Plan document for more complete information.

General

The Plan is a defined contribution plan. All State Street employees and certain related companies (collectively, the Company) are immediately eligible to participate in the Plan, except for the following categories of employees:

Plan Amendments and Other Changes

During 2007, the following amendments and changes were made to the Plan:

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State Street Salary Savings Program

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

During 2008, the following changes were made to the Plan:

Palmeri Fund Administrators, Inc.

Investors Bank & Trust Company

International Fund Services (N.A.) L.L.C.

Investment Management Services, Inc.

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State Street Salary Savings Program

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Contributions

Active participants may elect to make tax-deferred contributions and/or Roth after-tax contributions to the Plan equal to 1% to 50% of their compensation, subject to certain limitations. Participants may also contribute amounts representing rollover distributions from other qualified defined benefit or defined contribution plans.

Effective January 1, 2008, Matching Contributions to the Plan are made by the Company in amounts equal to 100% of the first 6% of the employee’s tax-deferred contributions or Roth after-tax contributions. Prior to January 1, 2008, contributions to the Plan were made by the Company in amounts equal to 50% of the first 6% of the employee’s contributions. Also, prior to January 1, 2008, all employees who had completed one year of employment during which they have worked at least 1,000 hours were eligible for corporate matching contributions.

All contributions to the Plan are paid to State Street Bank and Trust Company, as Plan Trustee. The Trustee holds contributions in trust exclusively for participants and their beneficiaries, invests the contributions as instructed by the participants, and makes benefit payments as they become due.

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State Street Salary Savings Program

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Vesting

Participant pre-tax deferral contributions and Roth after-tax contributions are always fully vested. Effective January 1, 2008, Matching Contributions and Performance-Based Contributions are 100% vested upon completion of one full year of employment with the Company, except in the event of death, disability, or retirement, in which case, Company contributions become fully vested. (Prior to January 1, 2008, Matching Contributions were fully vested immediately).

Forfeitures

Upon termination of employment, participants forfeit their non-vested balances. Forfeited balances of terminated participant’s non-vested accounts are used to reduce future Company contributions or pay Plan administrative expenses. Unallocated forfeitures balances as of December 31, 2008 and 2007 were approximately $208,653 and $18,762, respectively. No forfeiture money was used during 2008 and 2007.

Investment Options

Participant contributions and matching contributions are allocated to investment funds at the participant’s direction. A wide range of investment choices, including various common collective trust funds managed by State Street Bank and Trust Company, a mutual fund, a company stock fund (ESOP) and a Self-Managed Brokerage Account (SMBA), are available to participants. Limitations and restrictions apply to direct contributions to the ESOP or the SMBA funds.

In the event a participant does not make an investment election, and in the event of automatic enrollment, funds are invested in the Target Retirement Date Fund that corresponds to the participants assumed target retirement year based on the participant’s date of birth.

In-Service Withdrawals

The Plan provides that in-service withdrawals are available as follows:

Hardship withdrawals are available to satisfy an immediate and heavy financial need, provided the need cannot be satisfied with all other resources (as defined in the Plan).

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State Street Salary Savings Program

Notes to Financial Statements (continued)

1. Description of the Plan (continued)

Payment of Benefits

Upon retirement or other termination of employment, a participant eligible to receive a benefit may receive an immediate lump-sum distribution directly, or in the form of a rollover. If the vested value of the participant’s account balance is greater than $5,000, the participant may elect to defer the payment of their benefits and remain in the Plan, at which time the participant becomes non-active. If the value of the participant’s account balance is greater than $1,000, but not more than $5,000, a distribution in the form of an automatic rollover to an IRA will be made if the participant does not provide distribution instructions within 90 days of his or her termination date. Account balances of $1,000 or less will be automatically distributed to the participant in cash (by check) if no distribution instruction is received within 90 days of the participant’s termination.

Installment payments are available to participants who are retiree eligible at the time of termination. Installment periods available include monthly, quarterly, semi-annually, and annually.

Participant Loans

Participants may borrow from their fund accounts a minimum of $1,000, up to a maximum equal to the lesser of one-half of the participant’s vested balance, or $50,000. Loans are secured by the balance in the participant’s accounts, and bear interest at a rate comparable to a similar loan with a commercial institution. Repayment of principal plus interest is required within five years, unless the loan is for the purchase of a principal residence. Principal and interest are paid ratably through payroll deductions. In the event of termination of employment, participants with outstanding loans may elect to continue to repay their outstanding loan balance directly to the trustee; such loan shall not become immediately due and payable until such time as there is an event of a default.

Participant Accounts

Each participant’s account is credited with the participant’s contributions, Company contributions, and related earnings. The benefit to which a participant is entitled is the value of the participant’s vested account balance, including earnings.

Plan Termination

Although it has not expressed any intent to do so, the Corporation has the right under the Plan to discontinue its contributions at any time, and to terminate the Plan subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA). In the event of termination of the Plan, all participants will become fully vested.

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State Street Salary Savings Program

Notes to Financial Statements (continued)

2. Significant Accounting Policies

Basis of Accounting

The accounting records of the Plan are maintained on the accrual basis.

Investment Valuation and Income Recognition

Investments held by the Plan are stated at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). See Note 4 for further discussion of fair value measurements.

The Principal Preservation Fund (a common collective trust fund managed by SSgA known as State Street Bank and Trust Company Stable Fixed Income Fund for Employee Benefit Trusts) invests in fully benefit-responsive investment contracts. These investment contracts are recorded at fair value (Note 4); however, since these contracts are fully benefit-responsive, an adjustment is reflected in the statements of net assets available for benefits to present these investments at contract value. Contract value is the relevant measurement attributable to fully benefit-responsive investment contracts because contract value is the amount participants would receive if they were to initiate permitted transactions under the terms of the Plan. The contract value represents contributions plus earnings, less participant withdrawals and administrative expenses.

Purchases and sales of securities are recorded on a trade-date basis. Interest income is recorded as earned. Dividends are recorded on the ex-dividend date. Net appreciation (depreciation) includes the Plan’s gains and losses on investments bought and sold, as well as held during the year.

New Accounting Pronouncement

In September 2006, the Financial Accounting Standards Board (FASB) issued SFAS No. 157, Fair Value Measurements. This standard clarifies the definition of fair value for financial reporting, establishes a framework for measuring fair value, and requires additional disclosures about the use of fair value measurements. SFAS No. 157 was effective for financial statements issued for fiscal years beginning after November 15, 2007. Additionally, in October 2008, the FASB issued FASB Staff Position (FSP) 157-3, Determining the Fair Value of a Financial Asset When the Market for That Asset Is Not Active. FSP 157-3 clarifies the application of SFAS No. 157 in markets that are not active, and provides an example to illustrate key considerations in determining the fair value of a financial asset when the market for an asset is not active. The guidance in FSP 157-3 was effective upon issuance, including prior periods for which financial statements had not been issued. The Plan adopted SFAS No. 157 effective January 1, 2008.

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State Street Salary Savings Program

Notes to Financial Statements (continued)

2. Significant Accounting Policies (continued)

In April 2009, the FASB issued FSP 157-4, Determining Fair Value When the Volume and Level of Activity for the Asset or Liability Have Significantly Decreased and Identifying Transactions That Are Not Orderly. FSP 157-4 superseded FSP 157-3 and, while emphasizing that the objective of fair value measurement described in SFAS No. 157 remains unchanged, provided additional guidance on estimating fair value when the volume and level of activity for an asset or liability have significantly decreased in relation to normal market activity for the asset or liability. FSP 157-4 also provided additional guidance on circumstances that may indicate that a transaction is not orderly, and on defining major categories of debt and equity securities in meeting the disclosure requirements of SFAS No. 157. FSP 157-4 is effective for reporting periods ending after June 15, 2009. Plan management is currently evaluating the effect that the provisions of FSP 157-4 will have on the Plan’s financial statements.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Reclassification

Certain prior year amounts in the statements of net assets available for benefits have been reclassified to conform to the current year presentation.

3. Investments

During the years ended December 31, 2008 and 2007, the Plan’s investments (including investments bought, sold, and held during the year) appreciated (depreciated) in value as follows:

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State Street Salary Savings Program

Notes to Financial Statements (continued)

4. Fair Value Measurements

The Plan adopted SFAS No. 157 effective January 1, 2008. In addition, the Plan adopted FSP 157-3 upon its issuance in October 2008.

SFAS 157 defines fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (i.e., an exit price). SFAS No. 157 includes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets and liabilities (Level l), and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy under SFAS No. 157 are described below:

Following is a description of the valuation methodologies used for assets measured at fair value:

Mutual Funds: Valued at the net asset value of shares held by the Plan at year end as quoted in the active market.

Common Stocks and U.S. Government and Agency Securities: Valued at the closing price reported on the active market on which the individual securities are traded.

Corporate Bonds: Valued at quoted prices in markets that are not active, broker dealer quotations, or other methods by which all significant inputs are observable, either directly or indirectly.

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State Street Salary Savings Program

Notes to Financial Statements (continued)

4. Fair Value Measurements (continued)

Common Collective Trust Funds: Valued at the net asset value per unit held by the Plan at year end as quoted by the funds.

Participant Loans: Valued at amortized cost, which approximates fair value.

The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Plan believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement as of the reporting date.

The following table sets forth by level, within the fair value hierarchy, the Plan’s assets measured at fair value on a recurring basis as of December 31, 2008:

The table below sets forth a summary of changes in the fair value of the Plan’s Level 3 assets for the year ended December 31, 2008:

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State Street Salary Savings Program

Notes to Financial Statements (continued)

5. Transactions and Agreements with Parties-in-Interest

The Plan holds units of common collective trust funds managed by State Street Global Advisors, a related party of the Company. The Plan also invests in the common stock of the Company. These transactions qualify as party-in-interest transactions; however, they are exempt from the prohibited transactions rules under ERISA. During 2008 and 2007, the Plan received $4,768,570 and $4,742,047 common stock dividends from the Company, respectively. Investment fees and most costs and expenses associated with Plan administration and recordkeeping are paid by the Plan to certain related parties. These expenses are reported on the statements of changes in net assets available for benefits as administrative expenses.

6. Risks and Uncertainties

The Plan and its participants invest in various investment securities. Investment securities are exposed to various risks such as interest rate, market, liquidity, and credit risks. Due to the level of risk associated with certain investment securities, it is at least reasonably possible that changes in the values of investment securities will occur in the near term, and that such changes could materially affect participants’ account balances and the amounts reported in the statements of net assets available for benefits.

7. Income Tax Status

The Plan has received a determination letter from the Internal Revenue Service (IRS), dated February 2, 2009, stating that the Plan is qualified under Section 401(a) of the Internal Revenue Code (the Code), and therefore, the related trust is exempt from taxation. Subsequent to this determination by the IRS, the Plan was amended and restated. Once qualified, the Plan is required to operate in conformity with the Code to maintain its qualification. The plan sponsor has indicated that it will take the necessary steps, if any, to bring the Plan’s operations into compliance with the Code.

8. Reconciliation of Financial Statements and Form 5500

The following is a reconciliation of net assets available for benefits per the financial statements to Form 5500 as of December 31, 2008 and 2007:

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State Street Salary Savings Program

Notes to Financial Statements (continued)

8. Reconciliation of Financial Statements and Form 5500 (continued)

The following is a reconciliation of benefits paid to participants per the financial statements to Form 5500 for the year ended December 31, 2008:

Amounts allocated to withdrawing participants are recorded on Form 5500 for benefit claims that have been processed and approved for payment prior to December 31, but not yet paid as of that date.

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Supplemental Schedule

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State Street Salary Savings Program

EIN No.: 04-2456637 Plan No.: 002

Schedule H, Line 4i – Schedule of Assets (Held at End of Year)

December 31, 2008

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State Street Salary Savings Program

EIN No.: 04-2456637 Plan No.: 002

Schedule H, Line 4i – Schedule of Assets (Held at End of Year) (continued)

Note: Cost information has not been included because all investments are participant-directed.

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SIGNATURES

The Plan. Pursuant to the requirements of the Securities Exchange Act of 1934, the State Street Corporation Plans Investment Committee of State Street Corporation has duly caused this annual report to be signed by the undersigned hereunto duly authorized.

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Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the Registration Statement (Form S-8 No. 333-135695 and 2-68696) pertaining to the Salary Savings Program of State Street Corporation of our report dated June 26, 2009 with respect to the financial statements and schedule of the State Street Salary Savings Program included in this Annual Report (Form 11-K) for the year ended December 31, 2008.