Background: Vitamin D is an important factor for bone health. The prevalence of vitamin D deficiency in healthy young people is high. Thus, optimal supply of vitamin D may be of particular importance for bone health in children and adolescents with T1DM. Objective: To assess vitamin D status in prepubertal children with T1DM in Diabetic Endocrine Metabolic Pediatric Unit (DEMPU). Methods: In this cross-sectional study we assessed 30 Egyptian prepubertal children with T1DM clinically by full history taking and thorough clinical examination. Full history taking including; duration of diabetes, residence and sun exposure, type of diet especially low-fat diet, fortified formulas, and the intake of diet rich in vitamin D, life style and exercise in addition to the presence of bony aches or fractures. Thorough clinical examination laying stress on the anthropometric measurements (Wt.SDS, Ht.SDS, BMI), early signs of puberty and signs of associated disorders &/or diabetes complications. The records of the patients reviewed especially for HbA1c levels (done routinely every 3 months). We measured serum 25-hydroxy-vitamin D, iPTH, calcium in serum & diet, phosphate, and alkaline phosphatase. Results: The mean of serum vitamin D was 11.88+10.881ng/ml (low level). Despite the high prevalence of vitamin D deficiency, we found a low prevalence of secondary hyperparathyroidism (10%) in vitamin D deficient prepubertal children. There was no significant correlation between serum vitamin D and anthropometric measures, duration of diabetes, serum PTH, calcium, alkaline phosphatase, insulin dose, sun exposure, duration of diabetes, exercise, vitamin D in diet and calcium in diet.Conclusion: Prevalence of vitamin D deficiency in diabetic prepubertal children is high. Therefore, screening and supplementation of vitamin D may be considered.