A convenience sample of 587 subjects was selected from the waiting areas of community health centers in Harris County, TX. They completed a structured interview that included questions on their knowledge of acquired immunodeficiency syndrome (AIDS) transmission and prevention. Hispanic patients were interviewed in their preferred language. They were given a cumulative correct score for 10 questions on AIDS. An ANOVA showed significant differences in knowledge between each radial group. Cumulative scores were whites, 78 percent correct; blacks, 68 percent correct; and Hispanics, 61 percent correct. Only 58 percent of Hispanics reported that using a condom during sexual intercourse lowered the risk of contracting AIDS, compared with 84 percent of whites and 83 percent of blacks. A regression analysis showed significant effects for both education and racial group, but not for age and sex. These findings show that knowledge of AIDS can be predicted according to the race and education of the population using these community health centers. Additional attention should be focused on educating low-income blacks and Hispanics about AIDS.