We examined the relationship of HIV serostatus to drug use profile, high risk behavior, drug treatment status, and demographic characteristics of 505 intravenous drug users (IVDUs) in San Francisco. We found five identifiable drug-injection profiles described as Omnijector, Primarily Heroin, Primarily Heroin/Cocaine, Primarily Cocaine, and Primarily Speed which fell into "higher risk" and "lower risk" categories in relation to HIV seroprevalence of members (17.0 and 9.8%), respectively. This difference was not significant when effects of race were held constant (adjusted OR = 1.66, 95% CI = 0.91, 3.01). In logistic regression analysis, only Black race and age under 30 were significant predictors of HIV seropositivity (OR = 2.95, 95% CI = 1.57, 5.52 and OR = 2.05, 95% CI = 1.01, 4.13, respectively). Neither membership in higher risk profile nor frequency of injection (including daily or greater injection of cocaine) contributed to the model. We conclude that Black IVDUs under 30 are at greatest risk of HIV infection, that multiple patterns of drug use injection and habituation require additional resources to treat, and that the heterogeneous distribution of HIV weakens the predictive power of known behavioral risk factors in this population.