A seroepidemiologic study of human T cell lymphotrophic virus type-1 (HTLV-1) and human immunodeficiency virus (HIV) infections was carried out in Martinique among 467 pregnant women receiving prenatal care at the Martinique Department for the Protection of Motherhood and Childhood. A seroprevalence rate of 1.93% was found for HTLV-1 infection. No HIV serum marker was observed. Given the epidemiology of these viral diseases, it is suggested that serologic status should be determined for all pregnant women on this island. A further, large-scale, prospective survey of HIV seroprevalence in Martinique should be performed to confirm the results of the present study.