Exhibit 15
October 29, 2009
To the Board of Directors and Shareholders of Schering-Plough Corporation
We have reviewed, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the unaudited interim financial information of Schering-Plough Corporation and subsidiaries (the “Company”) for the three and nine-month periods ended September 30, 2009 and 2008, as indicated in our report dated October 29, 2009; because we did not perform an audit, we expressed no opinion on that information.
We are aware that our report referred to above, which is included in your Quarterly Report onForm 10-Q for the quarter ended September 30, 2009, is incorporated by reference in Registration StatementsNo. 2-83963,No. 33-50606,No. 333-30331,No. 333-87077,No. 333-91440,No. 333-104714,No. 333-105567,No. 333-105568,No. 333-112421,No. 333-121089,No. 333-134281,No. 333-153542 and333-162007 onForm S-8, Post Effective Amendment No. 1 to Registration StatementNo. 2-84723 onForm S-8, Post Effective Amendment No. 1 to Registration StatementNo. 333-105567 onForm S-8, Registration StatementsNo. 333-12909,No. 333-30355 andNo. 333-145055 onForm S-3 and Registration StatementNo. 333-159371 onForm S-4.
We also are aware that the aforementioned report, pursuant to Rule 436(c) under the Securities Act of 1933, is not considered a part of the Registration Statement prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of that Act.
/s/ Deloitte & Touche LLP
Parsippany, New Jersey
