Two hundred and fifty attendees at two London genitourinary medicine clinics were asked to complete an anonymous self-administered questionnaire, enquiring about sexual behaviour whilst abroad. Two hundred and forty-three questionnaires were evaluable. In the study group there were 116 women, and 127 men (62 heterosexuals and 65 homosexuals). Ninety women, 53 heterosexual men and 53 homosexual men had travelled abroad over the preceding 6 months. Of these 18 (20%) of women, 26 (51%) of heterosexual men and 19 (36%) of homosexual men had sex with a local foreign contact on holiday. Although both heterosexual and homosexual men were statistically more likely to have sex abroad with a local inhabitant, women were more likely to have unprotected sexual intercourse with a local partner. This has important implications for the spread of sexually transmitted disease including hepatitis B and HIV.