SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

Current Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 20, 2004

BANK ONE CORPORATION

(Exact name of registrant as specified in its charter)

Delaware

001-15323

31-0738296

(State or other jurisdiction

of incorporation)

(Commission File Number)

(IRS Employer

Identification No.)

1 Bank One Plaza, Chicago, IL 60670

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: 312-732-4000

Item 5. Other Events and Regulation FD Disclosure

See Item 12 below.

Item 7. Financial Statements, Pro Forma Financial Information and Exhibits

(c)

Exhibits.

Exhibit Number

Description of Exhibits

99(a)

Registrant’s April 20, 2004 News Release announcing its 2004 first quarter earnings.

Item 12. Results of Operations and Financial Condition

On April 20, 2004, the Registrant issued a news release announcing its 2004 first quarter earnings. A copy of the news release, including unaudited financial information released as a part thereof, is attached as Exhibit 99(a) to this Current Report on Form 8-K and incorporated by reference herein.

SIGNATURES

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

	BANK ONE CORPORATION (Registrant)


Date: April 20, 2004	By:	/s/ Heidi Miller
	Title:	Chief Financial Officer

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EXHIBIT INDEX

Exhibit Number		Description of Exhibits

99(a)		Registrant’s April 20, 2004 News Release announcing its 2004
		first quarter earnings.

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BANK ONE CORP 8-K