Data from the Substance Abuse and Mental Health Services Administration_s Integrated Database (IDB) were used to examine the service use patterns of individuals with possible opiate use disorders in Washington State. Results indicate that regardless of Medicaid enrollment status, individuals who received mental health (MH) or substance abuse (SA) services only through state agencies received no inpatient substance abuse service. Furthermore, when compared with individuals who received at least one MH/SA service through Medicaid, those who received services