March 25, 2005

Via U.S. Mail

Fred Hassan
Chief Executive Officer
Schering-Plough Corporation
2000 Galloping Hill Road
Kenilworth, N.J.

RE:		Schering-Plough Corporation
      Form 10-K for the fiscal year ended December 31, 2004
		File No. 1-6571

Dear Mr. Hassan:

      We have limited our review of your Form 10-K to disclosures
relating to your contacts with countries that have been identified
as
state sponsors of terrorism, and will make no further review of
the
Form 10-K.  Our review with respect to this issue does not
preclude
further review by the Assistant Director group with respect to
other
issues.  At this juncture, we are asking you to provide us with
supplemental information, so that we may better understand your
disclosure.  Please be as detailed as necessary in your response.
After reviewing this information, we may or may not raise
additional
comments.

      Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your
filings.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or on any other
aspect
of our review.  Feel free to call us at the telephone numbers
listed
at the end of this letter.



General -

We note that in Exhibit 21 to the Company`s 10-K for the fiscal
year
ended December 31, 2004, the Company lists an Iranian subsidiary
named Schering-Plough Limited.  In light of the fact that Iran has
been identified by the U.S. State Department as a state sponsor of
terrorism, and is subject to economic sanctions administered by
the
U.S. Treasury Department`s Office of Foreign Assets Control,
please
describe for us the extent of the Company`s operations in Iran;
the
materiality to the Company of any operations in Iran; and your
view
as to whether those operations constitute a material investment
risk
for your security holders.  In preparing your response please
consider that evaluations of materiality should not be based
solely
on quantitative factors, but should include consideration of all
factors, including the potential impact of corporate activities
upon
a company`s reputation and share value, that a reasonable investor
would deem important in making an investment decision.


Closing

      Please understand that we may have additional comments after
we
review your response to our comment.  Please contact Jack
Guggenheim
at (202) 942-7896 if you have any questions about the comment or
our
review.  You may also contact me at (202) 942-7817.



								Sincerely,




								Cecilia D. Blye, Chief
								Office of Global Security
Risk




cc: 	Jeffrey Riedler
		Assistant Director
		Division of Corporation Finance