In this survey, the knowledge, attitudes, beliefs, and behaviors concerning acquired immunodeficiency syndrome (AIDS) in a group (N = 196) of innercity adolescents in New York City were assessed. Sexual activity was the major risk factor for AIDS in this population; 58% of the adolescents had engaged in sexual intercourse; 12% of these had never used contraception. There were small reported rates of homosexuality, anal intercourse, and prostitution. Of respondents, 22% reported alcohol use and 22% had tried recreational drugs. None had ever taken drugs intravenously. Knowledge of human immunodeficiency virus (HIV) transmission was generally good, although there were prominent misconceptions. For example, 52% of the adolescents believed that donating blood could transmit HIV. Of respondents, 47% "never" or "rarely" worried about the disease. Of the total group, 39% reported behavior changes because of concern about AIDS in the previous 6 months. Those who changed behaviors tended to have a greater perceived risk, worry more frequently about the disease, and have a better knowledge of means of HIV transmission. Of those reporting behavior changes, 66% (25% of the total study group) claimed to be using condoms currently, and 16% (6% of the total study group) claimed to be abstemious. More black adolescents than Hispanic adolescents instituted behavior changes. Of black female adolescents, 71% were sexually active, as compared with 30% of Hispanic female adolescents.(ABSTRACT TRUNCATED AT 250 WORDS)