Background . The HIV epidemic in Eastern Europe and Central Asia continues to grow with most infections occurring in high-risk groups including people who inject drugs and their sexual partners. Labor migrants from this region who inject drugs while in Russia are at especially high HIV risk. Methods . We recruited 420 male Tajik migrant workers who inject drugs in Moscow for a peer-education HIV prevention intervention trial. Participants were interviewed about their sex and drug use behavior and tested for HIV and hepatitis C prior to the intervention. Results . Over half of the men reported injecting with a previously used syringe in the past month. Many men reported condomless sex (42%), multiple sex partners (30%), and sex with sex workers (42%). Only 17% had ever been tested for HIV. Despite substantial risk behavior, prevalence rates of HIV (6.8%) and HCV (2.9%) although elevated were lower than expected when compared to estimates of prevalence among PWID at the national level in Tajikistan. Risk behavior in diaspora varied across the men’s regional area of origin in Tajikistan and occupation in Moscow with HIV prevalence rates highest among those working at the bazaars. Conclusion . Tajik male migrants who inject drugs in Moscow are at heightened risk for HIV and hepatitis C. Evidence-based prevention approaches and messaging that specifically address the drug- and sex-related risk behavior of migrants from different parts of Tajikistan, employment sectors within the destination city, and socio-demographic background are needed.