This randomized double blind clinical trial compares the efficacy of buprenorphine maintenance treatment (BMT) and naltrexone maintenance treatment (NMT) for recently detoxified opioid dependent patients (N=130; 65 heroin dependent, 65 opium dependent—Specific Aim 1). Manual-guided, HIV risk reduction and drug counseling (DC-HIV) is provided to all patients as the platform psychotherapy. Maintenance treatment is provided for 12 weeks to all patients; patients may also continue to receive maintenance treatment for an additional 12 weeks following the initial treatment period. Primary outcome measures, assessed by twice weekly urine toxicology testing and self-report during the first 12 weeks and monthly during the 12-week extension, include resumption of heroin use, 1 and 3 weeks continuous relapse and reductions in HIV risk behaviors. The project will also evaluate the characteristics of treatment-seeking opioid addicts in Iran (including specific risk behaviors and patterns of HIV risk behaviors; prevalence of psychiatric and other medical comorbidity; and patterns of social, family, vocational, and criminal activity and service needs—Specific Aim 2). This data will be used to revise the DC-HIV manual to address the specific circumstances and risk behaviors of opioid addicts in Iran and to provide data regarding any differential response of opium compared to heroin addicts to BMT or NMT. Finally, the project will also provide clinical training for health professionals and training and mentoring in drug abuse treatment and HIV prevention research to clinical researchers who will continue development, implementation, evaluation and dissemination of HIV prevention and drug abuse treatment approaches in Iran after the project ends (Specific Aim 3). The Institute for Cognitive Science Studies will collaboratively fund the project and lead subsequent dissemination and drug abuse and HIV risk reduction efforts in Iran.