Background. To guide the development of an AIDS prevention program for urban minority high school students, the authors investigated the prevalence of AIDS-risk behaviors, and the relative explanatory power of demographic, contextual, and cognitive correlates of these behaviors, among black and Hispanic students in three New York City public high schools. Methods. A survey was administered to a randomly selected sample of classrooms in the 9th through 12th grades of three public academic high schools in a New York City borough. Survey participants (n = 926) were 59% black and 34% Hispanic; the mean age was 16.4 (sd 1.4) years. Results. Two-thirds of students reported having had sexual intercourse. of the more than one-half of students who reported past-year intercourse, three-quarters had never or had inconsistently used condoms, one-third had multiple intercourse partners, one-tenth had a sexually transmitted disease, and one-twentieth had intercourse with a high-risk partner. Demographic (i.e., age, race/ethnicity) and contextual (i.e., academic failure, substance use, adverse life circumstances, cues to prevention) factors were most strongly associated with involvement in AIDS-risk behaviors; in contrast, cognitive factors (i.e., knowledge and beliefs about AIDS and AIDS-preventive actions) had little explanatory power. Conclusions. Addressing demographic and contextual risk factors for involvement in AIDS-related behaviors may prove to be a more powerful AIDS-prevention strategy among adolescents than simply teaching facts about AIDS and fostering prevention-related beliefs.