The distribution of ABO and Rhesus blood group types was investigated in 984 randomly selected human T lymphotropic virus-1(HTLV-1)-infected blood donors from April 2004 to March 2007. A total of 1081 healthy controls admitted for blood donation in this period were enrolled in this study. Infected and control individuals were from the same region and their ABO/Rhesus blood group types were determined by the standard tube test technique. All blood samples were screened for HTLV-1 using an enzyme-linked immunosorbent assay (ELISA) and positive samples were confirmed by Western blot (WB). The unmatched analyses showed significant differences in frequency of the A+ blood group between healthy controls and HTLV-1-infected individuals (OR = 0.8, 95% CI = 0.66-0.97) and also a significant association was observed between these two groups(OR = 1.42, 95% CI = 1.1-1.99, p = 0.021). No significant difference in blood group (A-, B+, B-, O+, O-, and AB-) was observed between cases and controls. It is the first report of an association between HTLV-1-infected patients and ABO/Rh blood groups in our literature review. Our results might suggest that the A+ blood group decrease the risk of HTLV-1 infection in healthy controls, while the AB+ blood group is more frequent in HTLV-1 carriers and increases the risk of HTLV-1 infection.