We conducted a survey among female sex workers in Goroka, Eastern Highlands Province, Papua New Guinea to evaluate the frequency of sexually transmitted disease (STD) symptoms they suffered, their STD and HIV (human immunodeficiency virus) transmission knowledge and health-seeking behaviours, the forms that their HIV risk perception took, and the types and quantities of educational resources to which they had access and in fact used. This survey was a part of a larger study of sex workers that was carried out in two other cities, Lae, the capital of Morobe Province, and Port Moresby, the nation's capital. We interviewed 190 self-identified female sex workers who had been recruited between January 1999 and October 1999 through peer-mediated contacts. In an average one-week period, the women had intercourse with two customers, two to three times, and one boyfriend once or twice. In the surveyed group, 83% of the women had a history of symptomatic STDs and 73% had gone to an STD clinic for treatment. Of the women who used condoms at all, 7% used them each time they had sex with clients, but only 3% used them each time they had sex with steady partners. The remaining 93% of the women used condoms on some occasions or not at all. Most women (72%) knew about male-female transmission of HIV, but fewer cited other sexual and non-sexual modes of transmission. The majority of the women (71%) felt that they were of low or unknown risk of acquiring HIV infection. When asked where or to whom they would go when concerned about AIDS (acquired immune deficiency syndrome) or STDs, most women (93%) said that they would go to a health care provider. Evaluating the sex workers' understanding of STDs and HIV has been essential in designing education and intervention projects so as better to address the future morbidity and mortality associated with STDs and AIDS.