BACKGROUND: Although recent estimates of the HIV/AIDS burden in South Africa show the particular vulnerability of youth to HIV, HIV testing and its determinants are largely understudied in this age group. OBJECTIVE: To investigate the prevalence and determinants of HIV testing among young people aged 18 to 24 years, as part of an evaluation of the impact of loveLife. METHODS: South Africa's national HIV prevention campaign for young people, on HIV and related risk behaviours. A cross-sectional population-based household survey was conducted using a multistage stratified cluster sampling approach. The total sample included 3123 participants, aged 18-24, 54.6% men and 45.4% women, from four provinces (Eastern Cape, Gauteng, KwaZulu-Natal and Mpumalanga). RESULTS: The results indicated that over half (52.2%) of the youth reported testing for HIV, with more young females (60.1%) testing for HIV compared to their male counterparts (39.9%). In the multivariate analysis, older age, being female, HIV knowledge, having ever talked to the mother or female guardian about HIV and having ever been pregnant or made someone pregnant were found to be associated with testing for HIV. CONCLUSION: There is still room for improving the low proportion of young people who test for HIV. Specific attention needs to be paid to younger males, with lack of HIV knowledge, having never talked to the mother or female guardian about HIV and having never been pregnant or made someone pregnant were less likely to be tested. Outreach at individual and community levels and public health messages targeting these youth should be implemented.