الوصف In various genome-wide correlation studies, interleukin (IL)28B gene polymorphism has been strongly correlated with both the therapeutic and spontaneous mediated clearance of hepatitis C virus (HCV). Therefore, this study aimed to evaluate the genotype and allele frequency distributions of IL28B (rs12979860) in patients with chronic hepatitis C and assess the IL28B polymorphisms as predictors of sustained virological response to SOF-based therapy for HCV in Egyptian patients. This retrospective case-control study was conducted on 54 chronic HCV patients who completed treatment with SOF/DCV ± RBV for 12 weeks and responded to treatment with SVR12 (the responder group) as a control group, and 54 chronic HCV patients who completed treatment with SOF/DCV ± RBV for 12 weeks and did not respond to treatment and failed to achieve SVR12 (the non-responder group) as a case group. The CC genotype frequency of IL-28B (rs12979860) was greater in the responder group (51.9%). In contrast, the TT genotype frequency was higher in the non-responder group (48.1%) (p < 0.001), and the T allele significantly increased the risk of non-responses by 3.13 fold. Therefore IL-28B (rs12979860) SNP could be used as a genetic predictor of sustained virological