Available evidence suggests that young former Soviet Union immigrants in New York City have high rates of non-medical prescription opioid and heroin use, drug injection and injection-related risk behavior, making them vulnerable to hepatitis C virus (HCV)/human immunodeficiency virus (HIV) infection, overdose and associated harms. This group has been the focus of little research, however. This paper presents quantitative and qualitative data from 80 former Soviet immigrants (ages 18-29) to characterize their opioid use trajectories, injection risk behavior, HCV/HIV testing histories and self-reported HCV/HIV serostatus, and provides clinically meaningful data to inform tailored education, prevention and harm reduction interventions. [ABSTRACT FROM PUBLISHER]