This study examines the impact of alcohol use and HIV infection on neuropsychological performance in a sample of 497 community-resident African American men. HIV serostatus and alcohol use (during the past 12 months) exerted an interactive effect on psychomotor speed, reaction time, and motor speed, and in general, HIV infected heavy drinkers evidenced significantly poorer performance than other HIV positive subjects. Main effects for HIV serostatus were noted for reaction time, with seronegative men performing better than seropositives. This study examines a sample of men who continue to show increases in HIV infection, however, sample specific issues such as comorbid substance use, past histories of head injury, and lack of data on alcohol abuse and dependence require caution in definitively attributing the findings solely to alcohol and HIV. However, these findings suggest that relatively recent heavy alcohol use may represent a potential risk factor for more rapid or pronounced cognitive decline in HIV positive individuals, and that these patterns may be even more pronounced in persons with comorbid substance use.