This cross-sectional study sought to determine the percentage of individuals who met criteria for lifetime PTSD and HIV-related PTSD among 85 recently diagnosed HIV-positive patients attending public health clinics in the Western Cape, South Africa. The PTSD module of the Composite International Diagnostic Interview (CIDI) was used to determine the percentage of those who met criteria for lifetime PTSD and HIV-related PTSD. The rate of lifetime PTSD and incidence of HIV-related PTSD was 54.1% (95% CI: 43.6-64.3%) and 40% (95% CI: 30.2-50.6%), respectively. Findings suggest that receiving an HIV-positive diagnosis and/or being HIV-positive may be considered a stressor that frequently results in HIV-related PTSD. Given the various barriers to efficient mental health interventions and services in South Africa, there are significant challenges that need to be addressed in order to ensure that the mental health of HIV-positive individuals is appropriately addressed.