SC TO-C

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE TO

Tender Offer Statement under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934

CEPHALON, INC.
(Name of Subject Company (issuer))

CEPHALON, INC.
(Name of Filing Person (offeror))

2¹/2% Convertible Subordinated Notes due December 2006
(Title of Class of Securities)

156708 AD 1 and 156708 AE 9
(CUSIP Number of Class of Securities)

John E. Osborn, Esq.
Senior Vice President, General Counsel
and Secretary
Cephalon, Inc.
41 Moores Road
Frazer, PA 19355
(610) 344-0200
(Name, Address and Telephone Number of Person Authorized to Receive Notices
and Communications on Behalf of the Person(s) Filing Statement)

Copy to:
Pran Jha
Sidley Austin Brown & Wood LLP
Bank One Plaza
10 South Dearborn Street
Chicago, IL 60603

CALCULATION OF FILING FEE

Transaction Valuation:	Amount of Filing Fee:
Not applicable	Not applicable

o	Check box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the form or schedule and the date of its filing.
ý	Check box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes to designate any transactions to which this statement relates:

o	third party tender offer subject to Rule 14d-1	o	going-private transaction subject to Rule 13e-3
ý	issuer tender offer subject to Rule 13e-4	o	amendment to Schedule 13D under Rule 13d-2

Check the following box if the filing is a final amendment reporting the results of the tender offer.    o

Item 12. Exhibits.

Exhibit No.	Description
99.1	Text of Press Release issued on June 1, 2005.

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Exhibit Index

Exhibit No.	Description
99.1	Text of Press Release issued on June 1, 2005.

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Exhibit Index

EX-99.1

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	News
	Investor Contact: Chip Merritt 610-738-6376 cmerritt@cephalon.com
	Media Contact: Robert W. Grupp 610-738-6402 rgrupp@cephalon.com

For Immediate Release

Cephalon Announces Proposed Public Offering of
Convertible Senior Subordinated Notes

Plans to Use Portion of Net Proceeds to Tender for Outstanding
2¹/2 percent Convertible Subordinated Notes Due 2006

Frazer, PA—June 1, 2005—Cephalon, Inc. (Nasdaq: CEPH) announced today that it intends to offer, subject to market and other conditions, $800 million in aggregate principal amount of convertible senior subordinated notes due 2015 through a public offering. As part of the offering, Cephalon will grant the underwriters of the notes a 30-day option, solely to cover over-allotments, to purchase up to an additional aggregate $120 million principal amount of the notes.

        The annual interest rate on the notes is expected to be in the range of 1.5 percent to 2.0 percent, and the conversion price is expected to be between 10 percent and 14 percent above the last reported bid price of Cephalon common stock on The Nasdaq National Market on the date the notes are priced. The notes will be subordinate to existing and future senior indebtedness and senior to existing and future subordinated indebtedness of Cephalon. The offering is being made pursuant to an effective shelf registration statement previously filed with the Securities and Exchange Commission.

        Following the closing of this offering, the company intends to commence a tender offer to purchase all of its outstanding 2¹/2 percent Convertible Subordinated Notes due December 2006 at a price of 97.5 percent of the principal amount thereof. The company will use a portion of the net proceeds of this offering to purchase the outstanding 2¹/2 percent Convertible Subordinated Notes due December 2006. Cephalon also plans to use a portion of the proceeds of the offering to purchase convertible note hedge instruments with respect to Cephalon's common stock, which is expected to reduce the potential dilution from conversion of the new notes. In connection with those transactions, an affiliate of one of the underwriters will take positions in Cephalon's common stock in secondary market transactions and/or enter into various derivative transactions either before or after the pricing of the notes.

        Cephalon expects to use any remaining net proceeds from the offering to repay or repurchase certain other outstanding indebtedness or for working capital and other corporate purposes.

        The sole book-running manager will be Deutsche Bank Securities Inc.

        When available, a copy of the preliminary prospectus supplement and accompanying prospectus relating to the offering may be obtained from Deutsche Bank at 60 Wall Street, 4th floor, New York, NY 10005 or from the SEC at www.sec.gov.

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SOURCE: Cephalon, Inc. • 41 Moores Road • Frazer, PA 19355 • (610) 344-0200 • Fax (610) 344-0981

        This announcement is neither an offer to sell nor a solicitation to buy any of these securities and shall not constitute an offer, solicitation or sale in any jurisdiction in which such offer, solicitation or sale is unlawful.

Notice to Investors

        The tender offer for the Company's 2¹/2 percent Convertible Subordinated Notes due December 2006 will be made solely by and subject to the terms and conditions set forth in the offer to purchase and the related letter of transmittal, which will be included in a Tender Offer Statement on Schedule TO that will be filed by Cephalon with the SEC. The Tender Offer Statement (including the offer to purchase, the letter of transmittal and related documents) will contain important information which should be read carefully before any decision is made with respect to the tender offer. The offer to purchase and the related letter of transmittal will be delivered to holders of the 2¹/2 percent Convertible Subordinated Notes due December 2006. Cephalon's Tender Offer Statement will also be available for free from the SEC at www.sec.gov.

Cephalon, Inc.

        Cephalon currently markets three proprietary products in the United States: PROVIGIL® (modafinil) [C-IV], GABITRIL® (tiagabine hydrochloride) and ACTIQ® (oral transmucosal fentanyl citrate) [C-II] and more than 20 products internationally.

* * *

In addition to historical facts or statements of current condition, this press release may contain forward-looking statements. Forward-looking statements provide Cephalon's current expectations or forecasts of future events. These may include statements regarding anticipated scientific progress on its research programs, development of potential pharmaceutical products, interpretation of clinical results, prospects for regulatory approval, manufacturing development and capabilities, market prospects for its products, sales and earnings guidance, and other statements regarding matters that are not historical facts. You may identify some of these forward-looking statements by the use of words in the statements such as "anticipate," "estimate," "expect," "project," "intend," "plan," "believe" or other words and terms of similar meaning. Cephalon's performance and financial results could differ materially from those reflected in these forward-looking statements due to general financial, economic, regulatory and political conditions affecting the biotechnology and pharmaceutical industries as well as more specific risks and uncertainties facing Cephalon such as those set forth in its reports on Form 8-K, 10-Q and 10-K filed with the U.S. Securities and Exchange Commission. Given these risks and uncertainties, any or all of these forward-looking statements may prove to be incorrect. Therefore, you should not rely on any such factors or forward-looking statements. Furthermore, Cephalon does not intend to update publicly any forward-looking statement, except as required by law. The Private Securities Litigation Reform Act of 1995 permits this discussion.

# # #

SOURCE: Cephalon, Inc. • 41 Moores Road • Frazer, PA 19355 • (610) 344-0200 • Fax (610) 344-0981

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Cephalon Announces Proposed Public Offering of Convertible Senior Subordinated Notes