Objective Hyperinsulinemia plays an important role in the pathophysiological processes of chronic hepatitis C (CHC) and non-alcoholic fatty liver disease (NAFLD). However, there are few reports on hepatic insulin clearance in patients with these diseases. Methods A total of 74 CHC patients and 37 NAFLD patients were enrolled in this study. We evaluated their hepatic insulin clearance, insulin sensitivity and β-cell function with an oral glucose tolerance test. Results Hepatic insulin clearance in the patients with CHC was significantly correlated with platelets (r=0.271, p=0.020) and liver fibrosis (r=-0.234, p=0.045) and was significantly affected by both steatosis (mild: 0.157±0.078, severe: 0.114±0.053, p=0.024) and fibrosis (mild: 0.167±0.0857, severe: 0.125±0.052, p=0.010). There were no significant differences in (homeostasis model assessment) HOMA-β among steatosis and fibrosis stages. In the NAFLD patients, those with severe fibrosis had significantly reduced hepatic insulin clearance (mild: 0.135±0.045, severe: 0.098±0.031, p=0.013) and significantly increased HOMA-β (mild: 115.6±67.1, severe: 172.8±65.7, p=0.018) compared with the patients with mild fibrosis. Conclusion Liver fibrosis development is associated with hepatic insulin clearance in both the CHC and NAFLD patients.