Street sex workers represent an at-risk group of individuals who find it difficult to access mainstream health services. This was a cross-sectional study of street sex workers in Melbourne, Australia using a self-administered method to detect chlamydial, gonorrhoea and trichomonas infections. Of the 81 individuals approached, 63 (78%) (95% CI: 67-86%) agreed to participate. Overall, 87% of the participants obtained their results. Of the 63 participants, 53 (84%) had a past history of injecting drug use (95% CI: 73-92%), and 21 (33%) had a history of a sexually transmitted infection (STI) (95% CI: 22.0-46.3%). Neisseria gonorrhoeae was identified in 7 (11%) participants, Trichomonas vaginalis in 7 (11%), Chlamydia trachomatis in 1 (1.6%). None of the 19 (30%) participants who had been screened for an STI in the preceding 3 months were infected. Our results demonstrated that this method of testing for STIs was acceptable to the street sex workers, and demonstrated a disturbingly high proportion with infections.