Questcor Pharmaceuticals (QCOR) 8-K Changes in Registrant.s Certifying Accountant

Exhibit 16.1

April 11 , 2005

Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549

Gentlemen:

We have read Item 4.01 of Form 8-K dated April 11, 2005 of Questcor Pharmaceuticals, Inc. and are in agreement with the statements contained in the first, second and third paragraphs on page 2 therein. We have no basis to agree or disagree with the other statements of the registrant contained therein.

/s/ Ernst & Young LLP