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

September 13, 2004

Date of report (Date of earliest event reported)

ON Semiconductor Corporation

(Exact name of registrant as specified in its charter)

Delaware	000-30419	36-3840979
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification Number)

ON Semiconductor Corporation 5005 E. McDowell Road Phoenix, Arizona	85008
(Address of principal executive offices)	(Zip Code)

602-244-6600

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 7.01. Regulation FD Disclosure

On September 13, 2004, ON Semiconductor Corporation announced, via a news release, updated revenues and gross margin guidance for its third quarter of 2004. A copy of ON Semiconductor Corporation’s news release is attached hereto as Exhibit 99.

The information in this report (including its exhibit) shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (“Exchange Act”), or otherwise subject to liability of that section. The information in this report (including its exhibit) shall not be incorporated by reference into any registration statement or other document filed under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Item 9.01. Financial Statements and Exhibits.

(a) Financial Statements of Businesses Acquired

Not applicable.

(b) Pro Forma Financial Information

Not applicable.

(c) Exhibits

Exhibit No.	Description
99	News release for ON Semiconductor Corporation dated September 13, 2004 titled “ON Semiconductor Resets the Bar for the Third Quarter of 2004”

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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 thereunto duly authorized.

	ON SEMICONDUCTOR CORPORATION
	(Registrant)
Date: September 13, 2004	By:	/s/ DONALD A. COLVIN
		Donald A. Colvin
		Chief Financial Officer

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EXHIBIT INDEX

Exhibit No.	Description
99	News release for ON Semiconductor Corporation dated September 13, 2004 titled “ON Semiconductor Resets the Bar for the Third Quarter of 2004”

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