SecProbe.io

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                          [Schering-Plough Letterhead]

April 22, 2005

Cecilia D. Blye
Chief, Office of Global Security Risk
United States Securities and Exchange Commission
450 Fifth Street, NW
Washington, DC 20549

            RE:   FORM 10-K FOR THE FISCAL YEAR ENDED DECEMBER 31, 2004
                  FILE NO. 1-6571

Dear Ms. Blye:

      Your letter dated March 25, 2005 (received on April 4, 2005) to Fred
Hassan, Chief Executive Officer, inquiring about the extent and materiality of
any operations in Iran, was referred to me. I am senior counsel in the Office of
the Corporate Secretary, which is responsible for compliance with the federal
securities laws.

      Schering-Plough Limited (Iran), an indirect wholly owned subsidiary of
Schering-Plough Corporation (the "Company"), is a company organized under the
laws of Iran and has been dormant for many years. The Company recently conducted
a thorough review of the activities of Schering-Plough Limited (Iran) over the
past five years, and based upon that review is not aware of any commercial
activities by the Iranian affiliate. The Company currently maintains the status
of the Iranian subsidiary due to the potential legal barriers and costs of
reestablishing an entity in the event that U.S. sanctions against Iran are
lifted in the future and trade becomes permissible.

      The Company is committed to business integrity and has developed Standards
of Global Business Practices, which apply to all employees of Schering-Plough
Corporation and its subsidiaries worldwide (collectively the "affiliates"). The
Company recognizes that Iran is subject to U.S. trade and economic sanctions.
The Company has in place a comprehensive trade sanctions compliance program with
the goal of ensuring adherence to the applicable requirements of U.S. laws and
regulations including the U.S. sanctions against Iran. As part of this program,
the Company's International Law Group within the Law Department provides
guidance to the Company's U.S. and non-U.S. affiliates to assist the affiliates
in compliance with
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Cecilia D. Blye
Chief, Office of Global Security Risk
April 22, 2005

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all elements of U.S. foreign trade controls and to help ensure that any proposed
transactions with Iran by any non-U.S. affiliates fully comply with U.S. foreign
trade controls.

      The Company is aware that certain affiliates conduct business -- sales of
human prescription or over-the-counter medical products and sales of animal
health products -- with Iran. We believe these transactions do not involve any
prohibited involvement of U.S. persons, do not involve any prohibited use of
U.S. materials or technology, and, alone or in the aggregate, are not material.

      The Company does not believe that the sales to Iran constitute a material
investment risk to the Company's security holders. Sales to Iran are immaterial
to the Company. The Company and its affiliates are in compliance with U.S. laws
and regulations. Further, the Company does not believe there is any risk of
reputational damage in conducting sales to Iran to the extent allowed by U.S.
law. The Company's security holders are familiar with the Company's commitment
to improving the health and well-being of people around the world. Sales of
animal health products to Iran include vaccines for diseases in poultry and
cattle, which are important in providing a safe and adequate food supply. Sales
of human medical products include lifesaving prescription drugs and other drug
therapies that serve important medical needs in Iran. The Company does not
believe that the extension of its commitment to the people of Iran will have any
impact on its reputation or share price.

      If you have any questions or require additional information, please call
me at (908) 298-7355 or Susan Ellen Wolf, Corporate Secretary, at (908)
298-7354.

                                          Sincerely,

                                          Kara A. Sandler
                                          Senior Counsel, Corporate Law

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