Human platelet alloantigen systems are responsible for neonatal and post-transfusional thrombocytopenias. The determination of the different allotypes can be performed using immunological or DNA-based methods. The most used DNA-based procedure requires the digestion by specific restriction enzymes of PCR products containing the genetic determinants of these alloantigens. We now report a rapid method of genotyping which does not use restriction enzymes and is less prone to misinterpretation. This is non-radioactive PCR-SSCP (single strand conformation polymorphism), which we illustrate for two different HPA systems, one on GPIIIa (HPA-1) and the other on GPIIb (HPA-3).