POWER OF ATTORNEY

Know all by these presents, that the undersigned hereby constitutes and appoints
each of John E. Osborn, John M. Limongelli and Carolyn S. Iosca,
and each of them acting alone, signing singly, the undersigned's
true and lawful attorney-in-fact to:
(1) execute for and on behalf of the undersigned, in the undersigned's
capacity as an officer, director and/or 10% or more stockholder of
Cephalon, Inc. (the "Company"), Forms 3, 4 and 5 (and any amendments thereto)
in accordance with Section 16(a) of the Securities Exchange Act of 1934,
as amended (the "1934 Act"), and the rules promulgated thereunder;
(2) do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such
Form 3, 4 and 5 (and any amendments thereto) and to file timely such form
with the United States Securities and Exchange Commission and any
stock exchange or similar authority; and
(3) take any other action of any type whatsoever in connection with
the foregoing which in the opinion of such attorney-in-fact,
may be of benefit to, in the best interest of, or legally required by,
the undersigned, it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this
Power of Attorney shall be in such form and shall contain such terms
and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power
and authority to do and perform any and every act and thing whatsoever
requisite, necessary or proper to be done in the exercise of any of the
rights and powers herein granted, as fully to all intents and purposes
as the undersigned might or could do if personally present, with full
power of substitution or revocation, hereby ratifying and confirming
all that such attorney-in-fact, or such attorney-in-fact's substitute
or substitutes, shall lawfully do or cause to be done by virtue of
this power of attorney and the rights and powers herein granted.
The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned,
are not assuming, nor is the Company assuming, any of the undersigned's
responsibilities to comply with Section 16 and or the 1934 Act.

This Power of Attorney shall remain in full force and effect until
the undersigned is no longer required to file Forms 3, 4 and 5 with
respect to the undersigned's holdings of and transactions in securities
issued by the Company, unless earlier revoked by the undersigned in a
signed writing delivered to each of the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney
to be executed as of this 19th day of May 2005.


	/s/ Vaughn M. Kailian
	Vaughn M. Kailian