Our objective was to describe the clinical outcome and the association of fetomaternal platelet immunization in pregnancies with maternal Bernard-Soulier syndrome. We conducted an observational study of two mothers, six pregnancies, and six neonates, with special emphasis on platelet antibodies and thrombocytopenia-associated complications. The first woman presented with platelet-associated autoantibodies and thrombocytopenia, but her three newborn infants showed normal platelet count and function. The other woman had three pregnancies, all of which were complicated by severe fetal and neonatal alloimmune-type thrombocytopenia, without demonstrable antibodies. We concluded that fetomaternal immunization with severe fetal and neonatal thrombocytopenia may be encountered even in the absence of demonstrable antibodies.