Background and Aim: Chronic infection with hepatitis C virus (HCV) is a huge problem both globally and at the level of the individual patient. The natural outcome and response to treatment in hepatitis C virus (HCV) infection varies between individuals. Our aim is to detect the polymorphism of IL-10 gene at nucleotide (nt) -1082 and its protein level in the blood of chronic liver disease patients under treatment with interferon . Subject and Methods: Blood samples were taken from 100 patients who are suffering from chronic hepatitis C disease and prepared for interferon treatment. Also 20 blood samples from controls were taken. The following were done: history taking, general examination, liver function tests, hepatitis markers, HCV quantitation by real time PCR , DNA extraction from whole blood, PCR for gene amplification , agarose gel electrophoresis and quantitation of protein level of interleukin -10 by ELISA.Results: single nucleotide polymorphism (SNP) in the promotor region of the IL-10 gene (IL-10) at nucleotide (nt) -1082 show significant difference between responders and non responders (p=0.004) and by univariate and multivariate logistic regression it was a good predictor of response to hepatitis C therapy (p=.005) and (p= .003) respectively.Lower pretreatment plasma IL-10 protein were correlated with better response (p=.000). By univariate logistic regression analysis pretreatment, plasma IL-10 protein level was a good predictor of response to hepatitis C therapy (p=.017). Conclusion: SNP in the promotor region of the interleukin-10 gene (IL-10) at nucleotide (nt) -1082 and serum IL-10 protein level are predictors of response to combination therapy of HCV.