The HIV/AIDS epidemic in South Africa is rapidly escalating, and its demographic and social impact is beginning to be felt. Although the damage to the macro-economy is projected to be slight, the consequences for affected households will be dire, and social indicators such as life expectancy will deteriorate dramatically. A large majority of South Africans are affiliated to Christian Churches, but this has not prevented the types of sexual behaviour that promote the epidemic. Based on research in a KwaZulu township, this article presents evidence on the level of extra- and pre-marital sex (EPMS) among members of different church types. It is argued that only Pentecostal churches significantly reduce EPMS among members; and that they achieve this by maintaining high levels of four crucial variables: indoctrination, religious experience, exclusion and socialisation.