Thirty-two patients with coexisting substance abuse and other psychiatric disorders were treated in a unique outpatient pilot program that used techniques drawn from both psychiatric and substance abuse treatment. Eleven patients remained in treatment for 3 or more months, and seven completed a year or more of treatment. Severity of associated psychiatric illness did not affect retention in treatment. Drug-abusing patients and those with personality disorders dropped out quickly; patients with a history of reliable outpatient treatment involvement tended to remain in treatment. Treatment retention was associated with reduced hospital utilization. The authors suggest guidelines for management of patients with coexisting substance abuse and other psychiatric disorders.