OBJECTIVES: Identify predictors of multiple sclerosis (MS) disease-modifying drug (DMD) adherence.   METHODS: A random sample of adult MS patients from the US National Health and Wellness Survey or Lightspeed Research panel completed an internet survey in Nov/Dec2012. Clinical trial–naïve subjects with relapsing-remitting MS who were on their current DMD for ≥4months were included. Adherence was measured using the 4-item Morisky Scale. Patients were assigned to ‘high’ (negative response to all 4 questions: forget to take, careless at times about taking, stop if better, stop if worse) or ‘intermediate/low’ (any positive response). The survey contained demographic, disease characteristic and healthcare experience variables, which were evaluated as potential predictors of DMD adherence using logistic regression, controlling for age and gender. No adjustment was made for multiplicity. RESULTS: CONCLUSIONS: Patient and provider dialogue, patient satisfaction with treatment and health plan benefit design aspects may affect DMD adherence.