Infection with human retroviruses other than HIV in Spain has only been reported in isolated cases in African immigrants and intravenous drug abusers infected with HTLV-I. The status of the prostitute population is unknown. The sera of 88 prostitutes in Seville were therefore tested for HIV, HTLV-I and HTLV-II, and relevant epidemiological data were collected on the health status, sexual practices etc. In the prostitute population studied 2.5% of the non-intravenous drug abusers and 20% of the intravenous drug abusers were positive for HIV. However, infection with HTLV-I/II could not be demonstrated in any of them.