With an estimated 1.6-4 million opiate users (majority with injection drug use (IDU)) and more than 940,000 HIV infected individuals (80% linked to IDU), the Russian Federation is facing the prospect of an explosive HIV epidemic. Currently in Russia, inpatient detoxification followed by oral naltrexone maintenance (NMT) is the only pharmacologic treatment for opiate dependence. Evidence-based counseling to reduce HIV transmission and relapse following detoxification is not widely available or routinely provided. Several considerations, including data from our preliminary studies, suggest that the efficacy of NMT may be improved by using extended-release naltrexone (XR/NTX) instead of oral naltrexone (O/NTX) and by combining NMT with behavioral drug and HIV risk reduction counseling (BDRC). BDRC may also improve medication adherence and promote behavioral change leading to reduced relapse risk, IDU, and other drug- and sex-related HIV risk behaviors. However, the efficacy and cost-effectiveness for reducing drug- and sex-related HIV risk behaviors and increasing duration of opioid abstinence of the various combinations of naltrexone formulation (O/NTX vs. XR/NTX) and counseling (MM only or combined with BDRC) have not been systematically evaluated. Consequently, we are proposing a 2x2 factorial randomized clinical trial evaluating the efficacy and cost-effectiveness of two medication formulations (O/NTX and XR/NTX) and two manual-guided counseling conditions (MM only or MM+BDRC) and the potential interactions between medications and counseling conditions. Following detoxification, opiate dependent subjects (N=320) will be randomly assigned to 6 months of treatment in one of four treatment groups: O/NTX+MM, XR/NTX+MM, O/NTX+MM+BDRC, or XR/NTX+MM+BDRC. Primary outcome measures include reductions in sex- and drug-related HIV risk behaviors, reductions in illicit opiate use, and treatment retention. Other outcome measures include reductions in frequency of opiate or other drug use, health status and healthcare utilization, criminal behavior and arrests, and improvements in vocational and family functioning and quality of life. All study participants will be assessed at baseline and monthly during the 6 month treatment phase and for 6 months following the active treatment phase. Data analyses will focus on the intention-to treat sample. The study results will allow evaluation of whether XR/NTX has superior efficacy or is more cost-effective than O/NTX, whether BDRC plus MM has superior efficacy or is more cost-effective than MM only, and whether particular combinations of medications and counseling have superior efficacy or are more cost-effective than other combinations.