The aim of this study was to investigate the association between a genetic polymorphism of the vitamin D receptor (VDR) and antiviral responses in Egyptian patients with chronic hepatitis C virus genotype 4 (HCV-4). Methods: Our study enrolled 100 HCV-4 patients who received pegylated interferon alpha-2a (pegIFNα-2a) and ribavirin for 48 weeks. Patients were divided into 2 groups according to their response to therapy: 50 were responders, and 50 were nonresponders. All HCV-4 patients were further subjected to the following laboratory tests: HCV-RNA using quantitative PCR, vitamin D level using ELISA and VDR genotype using PCR-RFLP assays, and abdominal ultrasonography.Results: There was a statistically significant difference in the frequency of the VDR polymorphism (FokI rs10735810) between responders (FF:60%, Ff:16%, ff:24%) and non-responders (FF:10%, Ff:26%, ff:64%) (P<0.001). There was a statistically significant association between VDR polymorphism with higher ALT levels (ff: 63.2±30