Objective: Human T-cell lymphoma/leukaemia virus (HTLV-1) is a retrovirus implicated in transfusion-transmitted infection. The objective of this study was to determine the seroprevalence of HTLV-1 antibodies of blood donors and pregnant women in UNTH, Enugu, Eastern Nigeria and also compare the prevalence of HTLV 1 infection of blood donors and pregnant women. Methods: A cross-sectional study was carried out on five hundred (500) informed consented participants. Three hundred (300) blood donors were recruited from the blood bank and two hundred (200) pregnant women from the antenatal clinic. The recruitment was done consecutively. Five milliliters (5mls) of blood was collected from each of the participants into a plain sterile bottle and allowed to clot. The serum obtained was stored at -20oC until required for analysis. The serum samples were then analyzed for antibodies to HTLV-1 using a one-step incubation double antigen sandwich Elisa kit (Diagnostic Automation, USA). Participants’ demographic characteristics and degree of exposure to the risk factors associated with HTLV-1 infection were captured using a questionnaire. Statistical analysis of results was done using computer software namely Statistical Package for Social Science (SPSS) version 17, Microsoft Access and Excel.