A study of 150 hotel prostitutes in Lagos was undertaken to determine their socioeconomic identity and, through an assessment of their health knowledge, attitude, and practice, their probable impact on public health. The subjects were selected from 15 hotels, representing 20% of the estimated hotel universe in Lagos and different socioeconomic strata. Information was obtained from the subjects with the help of the hotel staff, who arranged pre-interview conferences with them. Prostitution in Lagos is not organised and there are no figures on the prostitute population. Ninety-eight per cent of the women in the study population were aged between 15 and 44 and 70% of them had children. Forty per cent were married and 24% were either divorced or separated. The most important reason given for prostitution was unhappiness in the home (50%) but the undercurrent of poverty, especially in a low-income society, is undoubtedly a major motive. More than half (55.3%) of the subjects selected their clients and the most important criteria for selection were physical fitness and ability to pay. Physical fitness was defined as the absence of signs of gonorrhea. The women's level of education was a significant factor in selection of clients and in mode of health care. More than 60% of those who selected their clients had had some education or had completed secondary schooling. Thirty-three per cent of those who did not select their clients had had no education at all and 45% had received primary education only. The attitude of the subjects to health care suggests an opportunity for the control of disease among prostitutes if prostitution is organised.