Background: HTLV I and II are human retroviruses that are endemic in the Sub-Saharan Africa including Nigeria and are associated with Adult T-cell Lymphoma/leukaemia, HTLV-I-associated Myelopathy/Tropical Spastic Paraparesis and Variant Hairy Cell Leukaemia. Blood transfusion is an efficient mode of transmission of the viruses with a seroconversion rate of about 63% and currently, screening of blood donations for HTLV I/II is not routinely carried out in Nigeria. Objective: The main objective of this study was to determine the prevalence of HTLV I/II among apparently healthy blood donors at the University College Hospital, Ibadan, Nigeria. Materials and Methods: A total of 1,000 apparently healthy blood donors were recruited in a descriptive, hospital based cross-sectional study at the Blood Bank of the University College Hospital, Ibadan and were screened for HTLV I/II by ELISA method.