We studied 11 patients with stable multiple sclerosis (MS) with major depression in terms of response to Sertraline at 100 mg q.d. in an open label trial. Patients were evaluated with self assessment measurements (Carroll scale) prior to and during treatment. Only one patient discontinued the drug during the three month treatment trial, and this was due to perceived lack of efficacy by the patient. The remainder of the patients completed at least three months of treatment and had significant improvement in depressive symptoms by self assessment measurements. No patients experienced side effects. Sertraline appears to be well tolerated and effective in treatment of major depression in MS. The Carroll scale is an easily administered means of assessing treatment response, and correlated highly with our clinical impressions.