Substance use by both HIV-infected victims and assailants during assault was high in this cohort of HIV-infected persons with a history of alcohol problems. The majority of assault victims reported that their assailants were using drugs during both physical and sexual assaults. Similarly, a large number of participants reported that they themselves were using substances when they were victimized, particularly in the course of physical assaults. Compared with men, women who were sexually assaulted were significantly more likely to report substance use by both themselves and their assailants. In a separate analysis that examined only the participants who experienced sexual assault after childhood (after age 13), women victims were still significantly more likely to report substance use during sexual assault than male victims. Women were also more likely than men to report substance use by their assailants. Reasons for gender differences in these findings require further investigation. The HIV-Alcohol Longitudinal Cohort recruited HIV-infected individuals with a history of alcohol problems, so as to evaluate the effect of alcohol use on HIV progression. The current study is a cross-sectional analysis. It used the baseline data of subsamples of the cohort who reported experiencing either sexual or physical assault. Data were collected on demographics, exposure to interpersonal violence, alcohol and drug use, and HIV transmission category. 2 tables and 41 references