Infection with human T-cell lymphotropic virus type I (HTLV-I) occurs mainly in Japan, Central and West Africa and the Caribbean Basin. Although antibody to HTLV-I has been reported among pregnant women in several endemic countries, there is no information regarding the seroprevalence in pregnant Ghanaian women. The reported seroprevalence of HTLV-I among healthy Ghanaian blood donors is between 0.5 and 4.2 %. Therefore, this study was conducted to determine the seroprevalence of HTLV-I among pregnant women attending the antenatal clinic at the 37 Military Hospital, Accra, Ghana, between the months of January and December 2003. The presence of antibodies specific for HTLV-I/II was tested using a particle agglutination test (PAT) kit and confirmed by Western blotting (WB). Of the 960 sera tested, HTLV-I/II antibodies were detected in 24 samples using the PAT kit. WB results indicated that, of the 24 positive PAT specimens, 20 specimens (83.3 %) were HTLV-I positive, one (4.2 %) was HTLV-II positive, two (8.3 %) were HTLV positive and one (4.2 %) was indeterminate. Therefore, the overall seroprevalence of HTLV-I was 2.1 %. Seroprevalence increased with age, suggesting sexual contact as the primary mode of transmission among women of childbearing age, rather than breastfeeding during infancy. The seroprevalence of 2.1 % reported here for HTLV-I in pregnant women in Accra is comparable to that of human immunodeficiency virus among the same population. In conclusion, the results indicate that HTLV-I is prevalent among asymptomatic Ghanaian pregnant women and thus there is a need to consider introducing antenatal screening for HTLV-I in Ghana.