Data from the 1989 Secondary School Student Health Risk Survey indicate that 54 percent of all high school students in the United States had had some form of HIV/AIDS education in school. Responses to a questionnaire on HIV/AIDS knowledge show that nearly all students knew the two main modes of HIV transmission--intravenous drug use and sexual intercourse. Students who had been taught about HIV and AIDS in school gave correct answers to questions about the virus more often than those who had not received instruction. Students who knew more about HIV transmission were less likely to report having had two or more sexual partners and more likely to report consistent condom use.