Community surveys have reported a higher rate of mental health problems in combined groups of homosexual and bisexual participants, but have not separated these two groups. To assess separately the mental health of homosexual and bisexual groups compared with heterosexuals. A community survey of 4824 adults was carried out in Canberra, Australia. Measures covered anxiety, depression, suicidality, alcohol misuse, positive and negative affect and a range of risk factors for poorer mental health. The bisexual group was highest on measures of anxiety, depression and negative affect, with the homosexual group falling between the other two groups. Both the bisexual and homosexual groups were high on suicidality. Bisexuals also had more current adverse life events, greater childhood adversity, less positive support from family, more negative support from friends and a higher frequency of financial problems. Homosexuals reported greater childhood adversity and less positive support from family. The bisexual group had the worst mental health, although homosexual participants also tended to report more distress.