Background Behavioural and other aspects of sexuality are not always consistent. This study describes the prevalence and overlap of same-sex and other-sex attraction and experience and of different sexual identities in Australia. Methods: Computer-assisted telephone interviews were completed by a representative sample of 20 094 men and women aged 16–69 years recruited by landline and mobile phone random-digit dialling with a response rate (participation rate among eligible people) of 66.2%. Respondents were asked about their sexual identity (‘Do you think of yourself as’ heterosexual/straight, homosexual/gay, bisexual, etc.) and the sex of people with whom they had ever had sexual contact and to whom they had felt sexually attracted. Results: Men and women had different patterns of sexual identity. Although the majority of people identified as heterosexual (97% men, 96% women), women were more likely than men to identify as bisexual. Women were less likely than men to report exclusively other-sex or same-sex attraction and experience; 9% of men and 19% of women had some history of same-sex attraction and/or experience. Sexual attraction and experience did not necessarily correspond. Homosexual/gay identity was more common among men with tertiary education and living in cities and less common among men with blue-collar jobs. Many gay men (53%) and lesbians (76%) had some experience with an other-sex partner. More women identified as lesbian or bisexual than in 2001–02. Similarly, more women reported same-sex experience and same-sex attraction. Conclusion: In Australia, men are more likely than women to report exclusive same-sex attraction and experience, although women are more likely than men to report any non-heterosexual identity, experience and attraction. Whether this is a feature of the plasticity of female sexuality or due to lesser stigma than for men is unknown.