Objective: To describe the characteristics of Australian adults' experience of commercial sex. Method: Telephone interviews were completed by a representative sample of 10,173 men and 9,134 women aged 16-59 years (response rate 73.1%; 69.4% men, 77.6% women). Respondents were asked about their experiences both as clients and as sex workers. Socio-demographic and health factors associated with experience of commercial sex were explored for men. Results: Almost one in six Australian men (15.6%) have ever paid for sex; 1.9% had done so in the past year. Of men who had ever paid for sex, 97% had paid for sex with a woman and 3% for sex with a man. Very few women (0.1%) had ever paid for sex. Twice as many men (0.9%) as women (0.5%) had ever been paid for sex; two-thirds of these men (0.6%) were paid by other men. Condom use during vaginal sex was highest in parlours and brothels and with escorts, and lowest for street sex work. Twothirds of women who had ever been paid for sex had done so only overseas. One in 10 men who had paid for sex had only done so overseas. Men who had paid for sex were more likely than other men to smoke, to drink more alcohol, to have had a sexually transmitted infection or been tested for HIV, to have more sexual partners, to have first had vaginal intercourse before 16, and to have had heterosexual anal intercourse. Conclusion: Sex work overseas, where condom use may not be common, represents a potential source of HIV or sexually transmitted infection.