This paper attempts to analyse historically why stigma and denial around HIV/AIDS is so powerful in South Africa, so powerful that ailing family members can be shunned and evicted. For many observers, the answer lies simply in its being a venereal disease, in its connotation with promiscuity and unregulated sexuality. We argue that this is not an adequate explanation. Pre-colonial African societies were relatively open about sexuality. Though pre-marital and adulterous pregnancy certainly caused social disruption, extra-marital sex per se was not stigmatised. Even the sexual shame introduced (unevenly) by Christianity and its hybridised forms is inadequate in explaining the degree of stigma associated with HIV/AIDS. We extend the discussion by exploring the stigma associated with various forms of pollution and the inevitability of death. The peculiarly interwoven mixture of sexual transgression, pollution and delayed death, we argue, makes HIV/AIDS an extraordinarily powerful generator of stigma.