In Africa, epidemiological data on the effect of the HIV epidemic on the occurrence of lymphomas are scanty. The 1990s witnessed the alarming rates of HIV/AIDS in Nigeria. The prevalence of HIV/AIDS in Nigeria increased from 1.8% in 1991 to 4.4% in 2005. The aim of this study was to determine whether there have been any changes in the frequency and pattern of lymphomas in view of the HIV/AIDS epidemic in the country. This is a retrospective study of all lymphoma cases diagnosed during 1991-2005. The prevalence of lymphomas declined from 1.4% to 0.7% of surgical biopsies during 1991-2005. There was a decline in the proportion of high-grade non-Hodgkin lymphoma and Burkitt's lymphoma from 79.1% and 45.8% respectively to 21.1% and 13.6% respectively. There is a suggestion that the HIV/AIDS epidemic in the country may not have influenced the pattern of occurrence of both major histomorphological types of lymphoma in Ibadan.