Background: Studying the predictors of SVR to pegylated interferon (PEG-INF) alfa-2a and ribavirin (RBV) therapy in chronic hepatitis C-infected patients is crucial for selecting those who would benefit from therapy. Increasing HPCs in hepatitis C-infected patients were shown to be correlated with increased fibrosis and response to therapy. HPCs could be detected in the liver by immunohistochemical expressions of cytokeratin (CK) 7 and CK19. This study aims to; 1. Evaluate the response rate to interferon based treatment in chronic hepatitis C-infected patients. 2. Detect the predictors of SVR to treatment. 3. Study the correlations between CK7 and CK19 expressions and treatment response. Subjects and Methods: This study included 483 chronic hepatitis C-infected patients who fulfilled the study criteria and underwent clinical, biochemical and virological assessments before treatment and at 12, 24, 48 and 72 weeks post-treatment. Only 330 patients completed the course and were included in the statistical analysis.  Only 50 specimens were examined for CK7 and CK19 expression using avidin, biotin, peroxidase technique. Results: SVR was achieved in 132/330 (40%) of patients. SVR was significantly higher in females (P<0.01), younger age group (P<0.004), and patients who had lower body mass index; BMI (P<0.001). There was significant inverse relation between SVR and aspartate aminotransferase (AST) and alpha feto-protein (AFP); P<0.000 and <0.000 respectively. The independent predictors of SVR were younger age and lower AST (P<0.02 and <0.02 respectively). There was significant association between CK7 and/or CK19 expressions and grade of necro-inflammation (P<0.033 and <0.026 respectively), and/or advanced stage of fibrosis (P<0.001 and <0.000 respectively). There were significant inverse relations between SVR and the stage of hepatic fibrosis (P<0.001), and CK19 expression (P<0.000). Conclusions: Forty % of patients with chronic hepatitis C who completed the course of combination therapy achieved SVR. Younger age and lower pre-treatment AST are independent predictors of SVR. In chronic hepatitis C, progenitor cell activation is correlated with the grade and stage of disease. Proliferating HPCs as assessed by CK7 and CK19 expressions may play a role in hepatic regeneration occurring in this setting and could be incorporated in assessment of treatment response of patients with HCV infection