Substance users may be at a heightened risk for the transmission of HIV and other blood-borne viral infections (BBVI) through injecting drug use or risky sexual behaviours. The current study aimed to investigate the engagement in BBVI-risk behaviours among a sentinel group of regular ecstasy users in Australia, with a particular focus on sexual practices and describe the occurrence of BBVI testing among this group. Participants were regular ecstasy users recruited across Australia in 2007 who were administered a structured interview that contained questions regarding substance use, sexual behaviours and occurrence of BBVI testing. Results indicate high levels of unprotected sex in the past 6 months (77% reported inconsistent condom use with a regular partner; 54% with a casual partner). Half the sample reported never having an HIV test. Unprotected sex was associated with being heterosexual; despite this, heterosexuals were also less likely to report HIV testing status. These data suggest that targeted health promotion messages may be needed for this group of predominantly young, heterosexual substance users who may fall out of the reach of traditional messages.