Objectives and Aim of the work: The aim of this study was to determine the level of vitamin D and to examine the relation between serum levels of 25(OH) D and disease activity in patients with JIA. Patients and Methods: 31 patients with Juvenile idiopathic arthritis (JIA) fulfilling the ILAR criteria for classification of JIA and 30 healthy individuals who served as controls participated in this study. All JIA patients were subjected to full history taking, clinical examination and laboratory investigations including assessment of serum level of 25(OH)D3. Results: High prevalence of vitamin D deficiency and insufficiency among Egyptian JIA patients (42%) was found. There is a statistically significant difference in serum vitamin D level between the number of the patients of the 2 JIA groups receiving vitamin D supplements (P=0.003).There is also a statistically significant difference on comparing the mean levels of 25(OH)D among the patients of the 2 JIA groups according to the dietary vitamin D intake (P=0.025) and highly significant difference according to the total vitamin D intake (P<0.001). On comparing between serum levels of 25(OH)D (ng/ml) according to drug intake, we found a statistically significant difference on comparing the patients taking and not taking NSAIDs (P=0.011). Also on dividing the JIA patients into 2 groups according to the vitamin D level, there is a significant relation between the number of patients receiving NSAIDs (P=0.027) and hydroxycloroquine (P=0.036) on one side and vitamin D level on the other side. No statistically significant relation was detected including the disease activity score JADAS-27. Conclusion: Egyptian Juvenile Idiopathic Arthritis (JIA) patients have high prevalence of vitamin D deficiency, but is not correlated to disease activity score JADAS-27.