The relative benefit of adding a structured psychoeducational intervention to standard medication treatment for married patients with bipolar disorder and their spouses was assessed. Patients were randomly assigned to receive either medication management or medication management plus a marital intervention with their spouses for an 11-month period. Patients' symptoms, functioning, and adherence to their medication regimens were measured at study entry and at 11 months. Significant effects favoring the combined treatments were observed for overall patient functioning but not for symptom levels. The marital intervention was associated with improved medication adherence. Combined psychosocial and medication treatment does not affect patients' symptom levels beyond the effects of medication alone, but it does result in significant incremental gains in overall patient functioning.