A review is presented of the association between the sex industry and the use and misuse of alcohol and illicit drugs. It is concluded that both the latter are associated with 'high risk' sexual activities and that heavy drinking and illicit drug use are commonplace amongst prostitutes and their clients. Outside Africa evidence suggests that in some, though by no means all, areas prostitutes have low or zero levels of HIV seropositivity. It is concluded that far more information is needed on the patterns of AIDS-related knowledge, beliefs, attitudes and behaviours amongst male and female prostitutes and their clients. Vigorous policies are needed to increase levels of knowledge about AIDS risks amongst prostitutes and their clients and to foster the adoption of 'safer sex' practices.