Utilization and cost of institutional and outpatient services were prospectively measured over 1 year for three groups of schizophrenic patients: current substance abusers, past substance abusers, and those without a history of substance abuse. Current abusers had significantly greater utilization and cost of institutional (hospital and jail) services. Current abusers also had greater utilization of emergency services. There were no significant differences between the groups in utilization and cost of other services, including psychosocial rehabilitation, outpatient treatment (case management, psychotherapy, and psychiatric visits), and housing supports. The implications for developing cost-effective treatments for dually diagnosed individuals are discussed.