Background : Primary immune thrombocytopenia is an autoimmune disorder characterized by autoantibody-mediated enhanced platelet destruction. BAFF gene polymorphisms increases BAFF expression and antibody production in ITP patients, which causes platelet destruction and megakaryopoiesis suppression Objective: To study the frequency of BAFF gene polymorphisms in newly diagnosed ITP in children and their association with it's clinical features and course. Methods: A case control study was conducted at Hematology Unit of pediatric department and Medical Biochemistry &Molecular Biology department at Zagazig University Hospital during a period from Nov. 2017 until Nov. 2018.The study Included 40 patients with newly diagnosed ITP (25 males and 15 females) and 20 age and sex-matched healthy children (11males and 9 females) as a control group. All children were subjected to a detailed medical history ,thorough clinical examination and Laboratory investigations including CBC , BM aspiration and B cell activating factor gene polymorphism (-871C/T) detection by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: There was also a highly significant difference between ITP cases and control regarding distribution of SNP of BAFF gene where CT was founded in 55% of ITP cases versus 25% in control; also, CC was founded in 75% of control versus 20% of cases. There was non-significant difference between different subtypes of BAFF gene polymorphism regarding age, gender, initial bleeding events,CBC, type of treatment and outcome of ITP cases. Conclusion: Significant association of BAFF gene polymorphism with newly diagnosed immune thrombocytopenic purpura in children may indicate its possible role in disease pathogenesis.