Injecting drug use is a common mode of transmission among persons with HIV/AIDS. Many HIV-infected patients meet diagnostic criteria for opioid dependence, a chronic and relapsing brain disorder. Most HIV providers, however, receive little training in substance use disorders. Opioid agonist therapy (OAT) has a stabilizing effect on opioid-dependent patients and is associated with greater acceptance of antiretroviral (ARV) therapy, higher ARV adherence, and greater engagement in HIV-related health care. Although methadone maintenance has been the OAT gold standard, methadone is available for the treatment of opioid dependence only in strictly regulated narcotic treatment programs. Buprenorphine, a partial opioid agonist approved for the office-based treatment of opioid dependence in 2002, may result in better health and substance use treatment outcomes for patients with HIV disease.