AIM: To study the frequency of vitamin D deficiency in patients with hepatitis C virus(HCV) infection and to evaluate the role of vitamin D supplementation in improving antiviral therapy.METHODS: Sixty-six children aged from 7-14 years(mean ± SD, 11.17 ± 2.293) diagnosed with HCV infection were matched to 28 healthy controls. Serum levels of 25(OH) D3, calcium, phosphorus, alkaline phosphatase and plasma level of parathormone were measured. Quantitative PCR for HCV was performed Bone density was determined by dual energy X-ray absorptiometry. All cases received conventional therapy, and only 33 patients received vitamin D supplementation.RESULTS: Children with HCV showed significantly increased levels of HCV RNA(P < 0.001), parathormone(P < 0.01) and decreased vitamin D levels(P < 0.05)(33.3% deficient and 43.3% insufficient) compared with controls. Abnormal bone status(Z score-1.98 ± 0.75) was found in ribs, L-spine, pelvis and total body. Cases treated with vitamin D showed significant higher early(P < 0.04) and sustained(P < 0.05) virological response. There was a high frequency of vitamin D deficiency among the Egyptian HCV children, with significant decrease in bone density. The vitamin D level should be assessed before the start of antiviral treatment with the correction of any detected deficiency. CONCLUSION: Adding vitamin D to conventional Peg/RBV therapy significantly improved the virological response and helped to prevent the risk of emerging bone fragility. AIM: To study the frequency of vitamin D deficiency in patients with hepatitis C virus (HCV) infection and to evaluate the role of vitamin D supplementation in improving antiviral therapy. METHODS: Sixty-six children aged from 7-14 years (mean ± SD , 11.17 ± 2.293) diagnosed with HCV infection were matched to 28 healthy controls. Serum levels of 25 (OH) D3, calcium, phosphorus, alkaline phosphatase and plasma level of parathormone were measured. Quantitative PCR for HCV was performed Bone density was determined by Dual energy X-ray absorptiometry. All cases received conventional therapy, and only 33 patients received vitamin D supplementation.RESULTS: Children with HCV HCV significantly increased (P <0.001), parathormone (P <0.01) and decreased vitamin D Levels (P <0.05) (33.3% deficient and 43.3% insufficient) compared with controls. Abnormal bone status (Z score-1.98 ± 0.75) was found in ribs, L-spine, pelvis and total body. signif There was a high frequency of vitamin D deficiency among the Egyptian HCV children, with significant decrease in bone density. The vitamin D level should be assessed before the start of antiviral treatment with the correction of any detected deficiency. CONCLUSION: Adding vitamin D to conventional Peg / RBV therapy significantly improved the virological response and helped to prevent the risk of emerging bone fragility.