Human platelet antibodies are often implicated in some disease conditions, such as neonatal alloimmune thrombocytopenia (NAIT), idiopathic thrombocytopenic purpura (ITP) and platelet refractoriness. There is paucity of information on the development and relevance of this antibody in pregnant black women, especially in Nigeria. This study was therefore designed to determine the occurrence of antiplatelet antibody in pregnant women. Eightynine (89) pregnant women attending a tertiary health facility in Osogbo participated in the study. Platelet count and human platelet antigens (HPA) were investigated using standard protocols of automation and ELISA respectively. Thirty-two(34%)of the women were thrombocytopenic and antiplatelet antibody was detected in 17(53%) of this sub-set. The antibody was of higher frequency in multiparous women and more prevalent within the age group of 26-30, especially those with history of previous blood transfusion. The study shows the imperativeness of including the platelet quantitative and functional assays as part of routine antenatal testing and monitoring.