Despite their presumed high risk for AIDS, there are almost no sexual behavior data available which are sufficient for the development and assessment of intervention programs for male prostitutes. This study was designed to obtain such data. Fifty 14–27‐year‐old male prostitutes in Manhattan were interviewed using structured instruments to assess sexual orientation, sexual behavior, knowledge of AIDS, and substance abuse. The sample was 50% homosexual, 26% bisexual, and 24% heterosexual. High rates of condom use were found for anal intercourse (average 85%). Subjects were safest in sex with male customers, less safe with male partners for pleasure, and least safe with female partners. Differential use of condoms plus other unsafe sexual activities continue to place the male prostitute at risk for HIV infection. AIDS knowledge was high and positively correlated with safety of sex. Drug and alcohol abuse and dependence were frequent, although there was little intravenous drug use. These and other variables were not significantly associated with degree of safety in sex. The methods employed in this study can be used to assess other populations of male prostitutes as well as intervention programs.