This article describes and compares distributions of drug-scene roles, frequency of engaging in role behaviors, and relationships of role-holding to high-risk behaviors and sexual partnerships among Puerto Rican injection drug users in New York and Puerto Rico. For this study 561 street-recruited injection drug users in East Harlem, New York, and 312 in Bayamón, Puerto Rico were asked the number of days (in the last 30) in which they earned money or drugs in each of seven drug-scene roles; and about behaviors and egocentric risk partner characteristics in the last 30 days. East Harlem subjects were more likely to get resources by selling drugs and syringes, and buying drugs for someone else; Bayamón subjects were more likely to be "hit doctors," buy needles for others, operate a shooting gallery, or escort others to shooting galleries. All roles were part-time except shooting gallery management in East Harlem. About 27% of respondents at each site engaged in two or more roles. Many roles were associated with increased odds of injecting more than twice a day, receptive syringe sharing, distributive syringe sharing, receptive paraphernalia sharing, and having a drug-injecting sex partner. Drug-scene role structures vary between cities. Most roles are part-time pursuits. Role-holders have higher-risk behaviors and sexual partnerships than other drug injectors. Although further research is needed, drug-scene role-holders should be targeted for interventions to affect their own risk and their communications with others.