OBJECTIVE: To determine the prevalence of penile wetness among STI clinic attenders in London. STUDY DESIGN: A total of 480 consecutive men were examined clinically to detect whether penile wetness, defined as the clinical observation of a uniform diffuse layer of moisture on the surface of the glans and coronal sulcus, was present. RESULTS: Penile wetness was observed in 30 (6.3%), including 29 (8.3%) of uncircumcised and 1 (0.8%) of circumcised men (Relative risk 10.54 (95% CI 1.45-76.6, P = <0.001) (Fisher's Exact test) and in 14/34 (41.2%) of men with balanitis. Penile wetness was observed in 9.2% Asian, 7% Caucasian, 3% of black men, and 6.3% of homosexuals, and in 14/34 (8.2%) of men with clinical balanitis compared with 8/244 (3.3%) with no STI diagnosis (P = <0.001). CONCLUSIONS: The prevalence of penile wetness was low in this population of STI clinic attenders in London, much lower than in Durban, South Africa. Further studies of male genital hygiene are warranted.