This study examines the association between drug and sexual HIV risk behaviors and knowledge of HIV serostatus among a sample of injection drug users, recruited into the 2009 National HIV Behavioral Surveillance project. We calculated prevalence ratios and associated 95% confidence intervals of reporting a given risk behavior comparing injection drug users unaware of their serostatus and HIV-negative to HIV-positive injection drug users. Of 523 participants, 21% were unaware of their HIV serostatus. The three groups were not different from each other in terms of drug-use behaviors; however, injection drug users unaware of their HIV serostatus were 33% more likely to report having more than three sexual partners in the past 12 months and 45% more likely to report having unprotected sex compared to HIV-positive injection drug users. We observed markedly higher prevalence of sexual risk behaviors among injection drug users unaware of their serostatus, but drug-use risk behaviors were similar across the groups.