Neonatal alloimmune thrombocytopenia (NAIT) is due to fetomaternal incompatibility for platelet specific antigens, most frequently HPA-1a (PLA1) and HPA-5b (BRa). It occurs in approximately 1/2.000-1/5.000 births. The most serious complication of NAIT is intracranial hemorrhage. The risk of life-threatening hemorrhage must lead to prompt diagnosis and effective therapy. Improvements in antenatal diagnosis and in utero therapy facilitate appropriate management of pregnancy at risk for NAIT. We report our experience with the serological diagnosis of 14 NAIT cases using new performing techniques such as western blotting (WB) and MAIPA (monoclonal antibody specific immobilization of platelet antigens).