The purpose of this study is to determine the difference in preventing a relapse between Betaseron and Avonex. Patients with RRMS currently treated with Avonex will be randomized into 2 equal-size arms; one arm will continue on the standard dose of Avonex; one arm will be converted to Betaseron standard dose.

This study has previously been posted by Berlex, Inc. Berlex, Inc. has been renamed to Bayer HealthCare Pharmaceuticals, Inc.Bayer HealthCare Pharmaceuticals, Inc.is the sponsor of the trial.

Inclusion Criteria:

• RRMS patients that are receiving treatment with Avonex 30 µg once weekly

Exclusion Criteria:

• Primary Progressive or Secondary Progressive MS