The authors describe a severely and persistently mentally ill (SPMI) opiate-addicted (OA) patient sample (n = 43) in a dual-diagnosis outpatient treatment program by demographic, clinical, and treatment characteristics and compare these with other dually diagnosed SPMI patients in the same treatment center (n = 297). Also, those SPMI/OA patients with physiological dependence (n = 20) were compared with a matched sample of OA patients in traditional methadone maintenance (n = 20). The authors then present a clinical evaluation of treatment course and outcome for the SPMI/OA patients (n = 43) and discuss implications from these pilot data.