UNITED STATES

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): October 2, 2012

PATHEON INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (919) 226-3200

Not Applicable

(Former name or former address, if changed since last report.)

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:

Prior to its fiscal year ending October 31, 2012, Patheon Inc. (the “Company”) prepared its annual consolidated financial statements in conformity with accounting principles generally accepted in Canada and provided a supplemental reconciliation to accounting principles generally accepted in the United States (“U.S. GAAP”). Effective November 1, 2011, the Company adopted U.S. GAAP as the reporting standard for its consolidated financial statements. Therefore, in order to present previously provided financial information on a basis that is comparable to the basis on which the Company prepared and reported similar information in its Quarterly Reports on Form 10-Q for the quarterly periods ended January 31, 2012, April 30, 2012 and July 31, 2012 (the “2012 Quarterly Reports”), the Company has recast its previously issued annual financial statements and certain other financial information originally reported within its Annual Report on Form 10-K for the year ended October 31, 2011 (the “2011 Form 10-K”), filed on December 19, 2011.

This Current Report on Form 8-K updates the following information that appeared in the 2011 Form 10-K:

The information set forth in this filing does not reflect events or developments that have occurred after December 19, 2011, the date the Company filed the 2011 Form 10-K, and does not modify or update the disclosures contained in the 2011 Form 10-K in any way other than as set forth above. Without limitation of the foregoing, this filing does not purport to update the Management’s Discussion and Analysis of Financial Condition and Results of Operations contained in the 2011 Form 10-K for any information, uncertainties, transactions, risks, events or trends that have subsequently occurred or have become known to management. More current information is contained in the 2012 Quarterly Reports and the Company’s other filings with the Securities and Exchange Commission (the “SEC”), and this Current Report on Form 8-K should be read in conjunction with the 2011 Form 10-K, the 2012 Quarterly Reports, and the Company’s other filings with the SEC.

(d) Exhibits.

See the Exhibit Index attached hereto.

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SIGNATURE

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.

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EXHIBIT INDEX