Immune thrombocytopenic purpura (ITP) is a bleeding disorder ofinfants, children, and adults. The majority of affected children have theacute form of ITP, defined by a duration of thrombocytopenia (< 150 x109/L) of < 6 months. Previous studies have shown that Fc gammareceptors (FcγRs) play crucial roles in platelet phagocytosis, antibodiesbound to platelets have their Fc portion exposed which allows binding tomonocytes/macrophages that express Fc receptors for IgG (FcγRs).The FcγRIIIa Valine (V) has increased affinity for three separateIgG subclasses when compared with the FcγRIIIa Phenylalanine (F).The aim of the present study is to assess the frequency ofoccurrence of the high affinity allelic variant FcγRIIIa – 158V inEgyptian children with ITP in comparison to normal individuals.Determination of FcγRIIIa genotype was performed for 30 ITPpatients and 10 healthy control subjects by nested PCR followed byRFLP analysis.In our study, the allelic frequency of FcγRIIIa – 158V was (76.6%)among ITP patient group in contrast to (20%) among the control group.These results suggest that FcγRIIIa – 158V/F polymorphism contributesto the pathogenesis of childhood ITP by increased clearance of antibodysensitizedplatelets by the high affinity FcγRIIIa – 158V allelic variant.