The relationship between frequent rehospitalization and compliance with treatment (medication and aftercare) was examined in a retrospective chart review of patients treated at an urban community mental health center over an 18-month period. Twenty-five patients who had been hospitalized three or more times during the study period were compared with a matched group of 25 patients who had been bospi talized less than three times and with the total group of 698 patients active at the center through out that period. The study found a highly significant correlation between noncompliance with medication and frequent rehospitalization. Compared with the general psychiatric patient population, frequently hospitalized patients tended to be younger and to have a chronic psychiatric illness, particularly one with an affective component, that featured at least intermittent psychosis. The author recommends study of outpatient commitment to treatment as a means of reducing noncompliance.