There is increasing evidence for the effect of rs12979860 IL28B polymorphism in response to the standard treatment PEG-IFN/RBV (i.e. combination of pegylated interferon and ribavirin) in chronic hepatitis C virus (HCV) infection. The present study aimed to determine the impact of IL28B associations in interferon responsiveness in 187 Moroccan patients with chronic HCV infection.HCV RNA levels were measured with a real-time RT-PCR assay and treatment efficacy was assessed by sustained virological response (SVR) and patients were classified as responders or non-responders. IL28B rs12979860 polymorphism genotyping was achieved by PCR-HRM technique.The results demonstrated that SVR was achieved in 102 patients (55%); while 69 were non-responders (37%) and 16 relapsed (8%). Genotype 1 was the predominant HCV genotype detected in 112 patients followed by genotype 2 in 56 patients. The genotype CC was observed in 42 cases (25%); CT in 69 (41%) and TT in 57 (34%) demonstrating a C allele frequency of 46%. The SVR was observed in 32 patients with genotype CC accounting for 76%. The frequencies of rs12979860 CC type in infected individuals with HCV genotype 1 were 47% and 12% respectively in SVR and non-SVR groups. A highly statistically significant association between this SNP and SVR was found (p<0.001). Using multivariate logistic regression analysis, CC genotype was an independent factor for SVR. In the group of patients infected with genotype 2, SVR rate was 79%. The frequency of rs12979860 CC type in SVR group (n=4) was 9% and rs12979860 non-CC genotype was highly associated with SVR (p=0.001).This finding adds evidence that genotyping for the IL-28B rs12979860 SNP can be a good parameter for the prediction of treatment success in patients with chronic hepatitis C before initiation of antiviral therapy in Morocco.