Cancer of the uterine cervix occurs with high frequency in black females of several populations of Southern Africa. It accounts for 40-50% of all cancers in Black females in the Johannesburg area and for over 40% of those in women in the rural lowveld area of the Transvaal. The aetiology of this cancer has several distinct features, almost all of which concern some or other aspect of coitus. Age at first coitus and at first marriage, and promiscuity, are very strongly associated with the development of the disease, and age, race, religion, culture, socio-economic status, extent of genital hygiene and venereal disease also play a major role. In spite of current belief, circumcision of the male partner is at best weakly associated with the development of the disease, and so are menstruation, coital habits and pregnancy. Certain aetiological features are selectively discussed; these include Herpesvirus type II, 'rogue' spermatozoa and the recent isolation of a group of potent carcinogens, the nitrosamines, in infected discharge samples taken from the vaginal vault of patients attending gynaecological clinics.