A network-oriented HIV prevention intervention based on social identity theory and peer outreach was implemented for HIV positive and negative drug users. A community sample of 250 were randomly assigned to an equal-attention control condition or a multisession, small-group experimental condition, which encouraged peer outreach; 94% of participants were African American, and 66% used cocaine or opiates. At follow-up, 92% of participants returned, and experimental compared with control group participants were 3 times more likely to report reduction of injection risk behaviors and 4 times more likely to report increased condom use with casual sex partners. Results suggest that psychosocial intervention emphasizing prosocial roles and social identity, and incorporating peer outreach strategies, can reduce HIV risk in low-income, drug-using communities.