QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)
OF THE SECURITIES EXCHANGE ACT OF 1934

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes [X]    No [  ]

Indicate by check mark whether the Registrant is an accelerated filer (as defined in Rule 12b-2 of the Exchange Act).    Yes [X]    No [  ]

Indicate the number of shares outstanding of each of the Registrant's classes of common stock as of the latest practicable date (March 31, 2005):

Wisconsin Energy Corporation is a diversified holding company which, during this reporting period, conducted its operations primarily in two operating segments: a utility energy segment and a non-utility energy segment. The sale of our former manufacturing segment was completed effective July 31, 2004, and is reported in the 2004 results as discontinued operations. Unless qualified by their context when used in this document, the terms Wisconsin Energy, the Company, our, us or we refer to the holding company and all of its subsidiaries. Our primary subsidiaries are Wisconsin Electric Power Company (Wisconsin Electric), Wisconsin Gas LLC (Wisconsin Gas) and W.E. Power, LLC (We Power).

Utility Energy Segment:   Our utility energy segment consists of: Wisconsin Electric, which serves electric customers in Wisconsin and the Upper Peninsula of Michigan, gas customers in Wisconsin and steam customers in metro Milwaukee, Wisconsin; Wisconsin Gas, which serves gas customers in Wisconsin and water customers in suburban Milwaukee, Wisconsin; and Edison Sault Electric Company (Edison Sault), which serves electric customers in the Upper Peninsula of Michigan. Wisconsin Electric and Wisconsin Gas operate under the trade name of "We Energies".

Non-Utility Energy Segment:   Our non-utility energy segment consists of We Power and Wisvest Corporation (Wisvest). We Power was formed in 2001 to design, construct, own, finance and lease to Wisconsin Electric the new generating capacity included in our Power the Future strategy, which is described further in this report. Wisvest owns and has investments in electric generating facilities and other energy-related entities and assets. As a result of a change in corporate strategy to focus on Power the Future, we have reduced the operations of Wisvest.

Other:   Other non-utility operating subsidiaries of Wisconsin Energy include Minergy Corp. (Minergy), which has $25.3 million of assets and develops and markets renewable energy and recycling technologies, and Wispark LLC (Wispark), which has $121.6 million of assets and develops and invests in real estate.

We have prepared the unaudited interim financial statements presented in this Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). We have condensed or omitted some information and note disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles pursuant to these rules and regulations. Our financial statements should be read in conjunction with the financial statements and notes thereto included in our 2004 Annual Report on Form 10-K.

WISCONSIN ENERGY CORPORATION
NOTES TO CONSOLIDATED CONDENSED FINANCIAL STATEMENTS
(Unaudited)

Our accompanying unaudited consolidated condensed financial statements should be read in conjunction with Item 8, Financial Statements and Supplementary Data, in our 2004 Annual Report on Form 10-K. In the opinion of management, we have included all adjustments, normal and recurring in nature, necessary to a fair presentation of the results of operations, cash flows and financial position in the accompanying income statements, statements of cash flows and balance sheets. The results of operations for the three months ended March 31, 2005 are not necessarily indicative of the results which may be expected for the entire fiscal year 2005 because of seasonal and other factors.

We have modified certain income statement, balance sheet and cash flow presentations related to the reporting of discontinued operations pursuant to Statement of Financial Accounting Standards (SFAS) 144, Accounting for the Impairment or Disposal of Long-Lived Assets. Previously, these were included as components of continuing operations. Prior year financial statement amounts have been reclassified to conform to their current year presentation. These reclassifications had no effect on total earnings per share.

Wisvest - Calumet:   On March 24, 2005, we entered into an agreement to sell our Calumet Energy (Calumet) facility for approximately $38.0 million in cash. The primary assets of Calumet are a 308 - megawatt natural gas-fired peaking power facility in Chicago, Illinois and related operating contracts. The agreement provides for customary closing conditions and representations and warranties. The sale is subject to Federal Energy Regulatory Commission (FERC) approval, and we anticipate closing the transaction in the second quarter of 2005. We anticipate that this transaction will generate a slight book gain upon closing and generate approximately $32.0 million in cash tax benefits.

As a result of the announced sale, we have reclassified the assets and liabilities of Calumet as Assets Held for Sale in the accompanying Consolidated Condensed Balance Sheets. In addition, we have recorded the operating results of Calumet as Discontinued Operations in the accompanying Consolidated Condensed Income Statements. Previously, Calumet's results were included in the non-utility energy segment.

WICOR Manufacturing:   Effective July 31, 2004, we sold our manufacturing business to Pentair, Inc. (Pentair). The accompanying 2004 Consolidated Condensed Income Statement reflects the operating results of this business in Discontinued Operations.

Pursuant to the terms of the sales agreement, Wisconsin Energy agreed to customary indemnification provisions related to certain environmental, asbestos and product liability matters associated with the manufacturing business. In addition, the amount of cash taxes and future deferred income tax benefits are subject to a number of factors including appraisals and applicable tax laws. We have established reserves related to the indemnification and tax matters.

The following table identifies the Operating Revenues and Pre-tax Income for Calumet and WICOR for the periods reported. These amounts are included in Discontinued Operations in the accompanying Statements of Income.

SFAS 143, Accounting for Asset Retirement Obligations, primarily applies to the future decommissioning costs for our Point Beach Nuclear Plant (Point Beach). SFAS 143 also applies to a smaller extent to several other utility assets including the dismantlement of certain hydro facilities and the removal of certain coal handling equipment and water intake facilities located on lakebeds. We have not recorded any asset retirement obligations for the removal of the coal handling equipment or for the water intake facilities located on lakebeds, because the associated liability cannot reasonably be estimated.

The following table presents the change in our asset retirement obligations, which are included on the consolidated balance sheet in Deferred Credits and Other Liabilities.

In March 2005, the Financial Accounting Standards Board (FASB) issued Interpretation 47, Accounting for Conditional Asset Retirement Obligations (FIN 47), an interpretation of FASB Statement No. 143. FIN 47 defines the term conditional asset retirement obligation as used in Statement No. 143. As defined in FIN 47, a conditional asset retirement obligation refers to a legal obligation to perform an asset retirement activity in which the timing and/or method of settlement are conditional on a future event that may or may not be within the control of the entity. We are currently evaluating FIN 47 but we do not expect an impact on the results of our regulated operations due to the regulatory treatment of asset retirement costs. FIN 47 will be effective for the fiscal year ending December 31, 2005.

Comprehensive Income:   Comprehensive income includes all changes in equity during a period except those resulting from investments by and distributions to owners. We had the following total comprehensive income during the three months ended March 31, 2005 and 2004:

Stock-Based Compensation:   We apply Accounting Principles Board Opinion No. 25, Accounting for Stock Issued to Employees, and related interpretations in accounting for our stock option plans and have adopted the disclosure-only provisions of SFAS 123, Accounting for Stock-Based Compensation, as amended. The following table illustrates the effect on net income and earnings per share as if we had accounted for stock options under the fair value method of SFAS 123 in each period. The fair value of options at date of grant was estimated using the Black-Scholes option-pricing model. Had we expensed stock-based compensation under SFAS 123, our diluted earnings per share would have remained unchanged for the three months ended March 31, 2005.

In December 2004, the FASB issued SFAS No. 123 (revised 2004), Share-Based Payment (SFAS 123R), which amended SFAS 123, Accounting for Stock-Based Compensation. In April 2005, the SEC deferred the effective date of SFAS 123R to January 1, 2006. This statement requires that the compensation costs relating to such transactions be recognized in the consolidated income statement. We are currently evaluating the provisions of SFAS 123R and expect to adopt it on January 1, 2006. We have not yet determined the method of transition.

Common Stock Activity:   In February 2004, we announced that we did not expect to issue new shares through our various employee benefit plans and the dividend reinvestment plan; rather, we instructed the plan agents to begin purchasing shares for the plans in the open market in lieu of issuing new shares.

During the first three months of 2005, we received proceeds of $18.9 million related to the exercise of stock options, compared with $14.8 million during the same period in 2004. We instructed our plan agent to purchase common stock in the open market at a cost of $29.8 million to fulfill the exercised stock options in the first quarter of 2005, compared with $26.3 million during the same period in 2004. This cost is included in Purchase of common stock on our Consolidated Condensed Statements of Cash Flows.

In January 2003, the FASB issued Interpretation 46, Consolidation of Variable Interest Entities (FIN 46). This standard requires an enterprise that is the primary beneficiary of a variable interest entity to consolidate that entity. We applied the Interpretation to any existing interests in variable interest entities beginning in the third quarter of 2003. In October 2003, the FASB deferred the adoption of FIN 46 for all entities commonly referred to as special-purpose entities to the first reporting period ending after December 15, 2003. In December 2003, the FASB issued FIN 46R, which revised FIN 46 and deferred the effective date for interests held in variable interest entities other than special purpose entities to financial statements for periods ending after March 15, 2004. We adopted FIN 46R in the first quarter of 2004.

We continue to evaluate our tolling and purchased power agreements with third parties on a quarterly basis. After making an exhaustive effort, we concluded that for three of these agreements, we are unable to obtain the information necessary to determine whether we are the primary beneficiary of these variable interest entities. Pursuant to the terms of two of the three agreements, we deliver fuel to the entity's facilities and receive electric power. We pay the entity a "toll" to convert our fuel into the electric energy. The output of the facility is available for us to dispatch during the term of the respective agreement. In the other agreement, we have rights to the firm capacity of the entity's facility. We have approximately $721.1 million of required payments over the remaining term of these three agreements, which expire over the next 18 years. We believe the required payments will continue to be recoverable in rates. We account for one of these agreements as a capital lease.

In March 2005, the FASB issued FSP FIN 46R - 5, Implicit Variable Interests under FASB Interpretation 46 (revised December 2003). This statement requires that holdings of implicit variable interests are evaluated when applying Interpretation 46R. An implicit variable interest is defined as an implied pecuniary interest in an entity that changes with changes in the fair value of the entity's net assets exclusive of variable interests. We are currently evaluating FSP FIN 46R - 5.

We follow SFAS 133, Accounting for Derivative Instruments and Hedging Activities, as amended by SFAS 149, Amendment of Statement 133 on Derivative Instruments and Hedging Activities, which requires that every derivative instrument be recorded on the balance sheet as an asset or liability measured at its fair value and that changes in the derivative's fair value be recognized currently in earnings unless specific hedge accounting criteria are met. For most energy related physical and financial contracts in our regulated operations that qualify as derivatives under SFAS 133, the Public Service Commission of Wisconsin (PSCW) allows the effects of the fair market value accounting to be offset to regulatory assets and liabilities.

We have a limited number of financial contracts that are defined as derivatives under SFAS 133 and qualify for cash flow hedge accounting. These contracts are utilized to manage the cost of gas used in testing a new generating unit under construction. Changes in the fair market values of these instruments are recorded in Accumulated Other Comprehensive Income. At the date the underlying transaction occurs, the amounts in Accumulated Other Comprehensive Income are capitalized.

The components of our net periodic pension and other post-retirement benefit costs for the three months ended March 31, 2005 and 2004 were as follows:

We previously disclosed that we expect to contribute $5.7 million to fund pension benefits in 2005, none of which will be for our qualified plans since there is no minimum required by law. Contributions to other post-retirement benefit plans are discretionary.

Employee Benefit Plans and Post-retirement Benefits:   In December 2003, the Medicare Prescription Drug, Improvement and Modernization Act of 2003 (Act) was signed into law. The Act introduced a prescription drug benefit program under Medicare as well as a federal subsidy to sponsors of retiree health care benefit plans. In the second quarter of 2004, the FASB issued FASB Staff Position (FSP) SFAS 106-2, Accounting and Disclosure Requirements Related to the Medicare Prescription Drug, Improvement and Modernization Act of 2003.

In accordance with FSP 106-2, we chose to recognize the effects of the Act retroactively effective January 1, 2004 with the impacts calculated actuarially. In January 2005, the Centers for Medicare & Medicaid Services released final regulations to implement the new prescription drug benefit under Part D of Medicare. It was determined that the employer sponsored plans meet these regulations and that the previously determined actuarial measurements are still accurate. The final regulations have not yet addressed account based plans similar to the Cash Balance Medical Plan covering former Wisconsin Gas employees. These plans are expected to be addressed by regulations to be issued in 2005. At this point, we do not expect that the final regulations will change our estimates.

Severance Plans:   We incurred $30.5 million ($18.3 million after-tax) of severance costs in 2004. The majority of the severance costs related to an enhanced severance package offered to selected management employees of Wisconsin Energy and its subsidiaries who voluntarily resigned in the fourth quarter of 2004. During the first quarter of 2005, we made severance related payments that reduced the reserve for severance benefits from $6.6 million at December 31, 2004 to $2.6 million as of March 31, 2005.

We enter into various guarantees to provide financial and performance assurance to third parties on behalf of affiliates. As of March 31, 2005, we had the following guarantees:

A Non-Utility Energy guarantee in support of Wisvest-Connecticut, which we sold in December 2002 to PSEG, provides financial assurance for potential obligations relating to environmental remediation under the original purchase agreement for Wisvest-Connecticut with United Illuminating. The potential obligations for environmental remediation, which are unlimited, are reimbursable by PSEG under the terms of the sale agreement in the event that we are required to perform under the guarantee.

Other guarantees support obligations of our affiliates to third parties under loan agreements and surety bonds. In the event our affiliates fail to perform, we would be responsible for the obligations.

Wisconsin Electric guarantees the potential retrospective premiums that could be assessed under Wisconsin Electric's nuclear insurance program.

Subsidiary guarantees support loan obligations between our affiliates and third parties. In the event the loan obligations are not performed, our subsidiary would be responsible for the obligations.

Postemployment benefits:   Postemployment benefits provided to former or inactive employees are recognized when an event occurs. The estimated liability, excluding severance benefits, for such benefits was $16.5 million as of March 31, 2005 and $15.6 million as of December 31, 2004.

Summarized financial information concerning our reportable operating segments for the three month periods ended March 31, 2005 and 2004 is shown in the following table.

Environmental Matters:   We periodically review our exposure for remediation costs as evidence becomes available indicating that our remediation liability has changed. Based on current information, we believe that future costs in excess of the amounts accrued and/or disclosed on all presently known and quantifiable environmental contingencies will not be material to our financial position or results of operations.

Cautionary Factors Regarding Forward - Looking Statements:   Certain statements contained herein are "Forward-Looking Statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-Looking Statements include, among other things, statements regarding management's expectations and projections regarding completion of construction projects, regulatory matters, fuel costs, sources of electric energy supply, gas deliveries, remediation costs, environmental and other capital expenditures, liquidity and capital resources and other matters. Also, Forward-Looking Statements may be identified by reference to a future period or periods or by the use of forward looking terminology such as "anticipates," "believes," "estimates," "expects," "forecasts," "intends," "may," "objectives," "plans," "possible," "potential," "projects" or similar terms or variations of these terms. Actual results may differ materially from those set forth in Forward-Looking State ments as a result of certain risks and uncertainties, including but not limited to, those risks and uncertainties described under the heading "Cautionary Factors" in this Item 2, as well as other matters described under the heading "Factors Affecting Results, Liquidity and Capital Resources" in this Item 2, and other risks and uncertainties detailed from time to time in our filings with the SEC or otherwise described throughout this document.

The following table compares our net income during the first quarter of 2005 with similar information during the first quarter of 2004 including favorable (better (B)) or unfavorable (worse (W)) variances.