Using data from Australian Gay Community Periodic Surveys 1998-2010, we assessed the prevalence, trends and characteristics of gay men not tested for HIV. In 2010, one in eight Australian gay socially-engaged men were never tested for HIV, most of them sexually active and 56.5 % reporting unprotected anal intercourse. The proportion of not tested men was significantly higher in men younger than 30, of non-European origin and living outside of gay metropolitan areas. Although frequency of testing was associated with sexual practices, significant proportions of men with multiple sex partners and reporting unprotected anal intercourse were not tested as recommended. There were issues with using gay-friendly testing services in gay metropolitan areas. Despite Australia's success in HIV testing, improvement is needed for early detection of HIV infections. Interventions should encourage regular testing, engage with young gay men, improve access and convenience of testing, train service providers and expand testing options.