Background: Disease-modifying therapies (DMTs) for the treatment of multiple sclerosis (MS) are associated with inconvenient methods of administration, significant side effects, and low adherence rates. This study was undertaken to compare treatment satisfaction in MS patients treated with interferon beta-1a intramuscular (IFNβ-1a IM), interferon beta-1a subcutaneous (IFNβ-1a SC), glatiramer acetate (GA), and natalizumab (NTZ), and to examine the associations between treatment satisfaction ratings and adherence to therapy.