There is a high burden of underlying substance use and mental illness in HIV-infected populations. HIV-care settings provide an important opportunity to assess substance and mental health needs among HIV-positive patients and to provide or make referrals for appropriate treatment services. In 2003, with funding from the Center for Substance Abuse Treatment (CSAT), we developed a model of integrated substance-use counselling and referral for treatment within a primary care HIV-care setting at The Miriam Hospital in Providence, Rhode Island. The project uses a multidisciplinary approach to provide linkage to treatment services for substance use and mental illness as well as to help participants with social service needs, such as housing and medical coverage, to ensure continuity of care and optimal HIV treatment adherence. Twelve percent of the 965 HIV-infected patients in care at our center have been enrolled in the project. Of these, all have a current substance-use disorder and 79.3% have been diagnosed with a mental illness. In addition, most participants are hepatitis C-positive (HCV) (65.5%). The majority of participants are on antiretroviral therapy (76.7%). Participants have been referred for the following treatment modalities: intensive outpatient services, methadone, buprenorphine, outpatient services and residential as well as individual and group counselling. Our model has been successful in assessing the substance-use and mental health needs of HIV-infected individuals with numerous co-morbidities and referring them for ancillary medical and social services.