Human immunodeficiency virus (HIV) related cancers in children are not as common and as well described as in adults. An HIV epidemic has been prevalent in Zambia since 1983-1984. To study the effect of the epidemic on the epidemiology of cancers in children a retrospective study was undertaken at the University Teaching Hospital (UTH), Lusaka, Zambia. All the histopathological records from 1980 to 1992 were reviewed and all cases of cancers in children less than 14 years of age were analysed. In order to define the effect of the HIV epidemic, the epidemiological features of various childhood cancers occurring before (during the years 1980-1982) and after (during the years 1990-1992) the onset of the HIV epidemic were compared. A significant increase in the occurrence of total childhood cancers was found. This is mostly due to a highly significant increase in the incidence of paediatric Kaposi's sarcoma (p = 0.000016), which is causally related to HIV infection, and a significant increase in the incidence of retinoblastoma (p = 0.02), which has an unknown relation to HIV infection. Though not yet statistically significant, there has also been a gradual and sustained increase in the incidence of non-Hodgkin's lymphoma, nasopharyngeal carcinoma, and rhabdomyosarcoma. There has been a significant reduction in the incidence of Burkitt's lymphoma. A prospective in depth epidemiological study of HIV related childhood cancers in Africa is urgently needed.