Background: Vitamin D, affecting many tissues and organs of the body. It exerts many of its effects through contact with Vitamin D receptor (VDR) It Is Important especially in immune system; Immune thrombocytopenia is one of the most common causes of symptomatic thrombocytopenia in children. Aim: The main objective of our study was to study vitamin D receptor level in children with immune thrombocytopenic purpura and effect of vitamin D supplementation upon the response of the thrombocytopenia to conventional therapy of ITP. Subjects and Methods: This is a case control study which included 30 ITP children, who would be attendants to Hematology and Oncology Unit, Pediatric Department, Tanta University Hospital in Egypt. This study would include also 30 apparently healthy children matched in age and sex as a control group. The duration of the study ranges from 6 to 12 months, for all patients and controls the following were done: complete blood count, bone marrow aspiration, serum level of Vitamin D receptors, serum calcium level, serum phosphorus level, serum alkaline phosphatase level and serum parathyroid hormone level. Results: the results revealed that mean ± SD of Vitamin D receptors in case group is 132.43 ± 14.58 and there was statistical difference between groups regarding Vitamin D receptor. There was statistical difference between platelets count and Serum total Ca (mg/dl) with negative correlation, while there was no statistical difference between platelets count and Vitamin D receptor. There was statistically significant difference in platelets count in patient with ITP before and after conventional treatment and platelets count in patient with ITP under conventional treatment plus vitamin D supplementation. Conclusion: VD receptors elevation is very common in ITP. Supplementing VD might diminish recurrence. Further research is needed.