According to mathematical modeling, HIV is more likely to spread through a population of men who have sex with men when high numbers practice versatile anal sex roles, that is, engage in both insertive (IAI) and receptive anal intercourse (RAI). Yet, actual patterns of versatility remain largely unknown, particularly among older men who currently face growing rates of HIV. In this study, 1,135 Australian gay men aged 40 years and older completed a national online survey of their sexual health and behavior over the past 12 months. Of men who had anal intercourse, 62 % engaged in both IAI and RAI. Factors associated with being versatile included younger age (P = 0.01), higher income (P = 0.009), and larger numbers of sexual partners (P = 0.003). Among men with multiple sexual partners, 20 % were highly versatile, that is, reported similar numbers of IAI and RAI partners. Having HIV (P = 0.003) and living in a rural area (P = 0.04) were significantly associated with being highly versatile. These data point to high rates of versatility among older Australian gay men, with implications for mathematical predictions of change in HIV epidemics and for the design of future HIV prevention strategies.