The results from a telephone survey in 2001-02 of a probability sample of Australian households including 10,173 men aged 16-59 (response rate 69.4%) are used to assess the prevalence of circumcision across social groups in Australia and examine lifetime history of sexually transmissible infection (STI), sexual difficulties in the last year, sexual practices including masturbation, and sexual attitudes. More than half (59%) of the men were circumcised. Circumcision was less common among younger men (32% aged <20) and more common among the Australian born (69%). After correction for age, circumcision was unrelated to reporting STI, but appeared to protect against penile candidiasis. Circumcision was unrelated to most sexual difficulties, but circumcised men were less likely to report physical pain during intercourse or trouble keeping an erection; reasons for this are unknown. There were no significant differences in practices at last sexual encounter with a female partner or in masturbation alone. Circumcised men had somewhat more liberal sexual attitudes. Neonatal circumcision was routine in Australia until the 1970s. It appears not to be associated with significant protective or harmful sexual health outcomes. This study provides no evidence about the effects on sexual sensitivity.