There is a complex relationship between Diabetes mellitus (DM) and chronic Hepatitis C (CHC). DM is common in CHC patients and at the same time it reduces the therapeutic effectiveness of pegylated interfer¬on (Pegyl.IFN) and ribavirin therapy. The aim of the study was to exam¬ine the influence of DM on the Sustained Virological Response (SVR) af¬ter Pegyl IFN, ribavirin therapy in Egyptian CHC patients and to study the incidence of glucose abnormalities developed in non diabetic CHC patients with treatment and its relation to the SVR. Methods: 256 Egyptian CHC patients were divided into 2 groups: Group (1): 116 dia¬betic patients, and Group (2): 140 Non diabetic patients. All patients re¬ceived Pegyl IFN and ribavirin for 48 weeks and monitored for SVR and glucose abnormalities development during 12 months after end of treat¬ment. Results: SVR of the studied groups was 50.8%, diabetic patients had less SVR than non diabetic (40.50% vs. 59.30%, 13=0.003), and on multivariate analysis, diabetic patients had significantly older age [0.R 1.06, 95% C.I (1.016-1.114)p 0.0081 higher BMI 11.204 (1.020-1.422)p 0.031 and more statuses [1.565 (1.21-2.20) p 0.0011. Higher SVR was associated with lower fasting and post prandial blood sugar (p