['The role of insulin resistance in predicting virological response to therapy of chronic hepatitis C is debated. We assessed the association between basal (defined as homeostasis model assessment of insulin resistance (HOMA-IR)>2) and post-load insulin resistance (as oral glucose insulin sensitivity index<9.8 mg/kg/min) with the rapid and sustained virological responses in chronic hepatitis C.', 'Observational prospective study of 124 treatment-naïve patients with chronic hepatitis C not fulfilling the metabolic syndrome criteria, adherent to a standard treatment with pegylated interferon alpha plus ribavirin.', 'Insulin resistance was detected in 50% (by HOMA-IR) and 29% (by oral glucose insulin sensitivity index) of patients. Independent predictors of rapid virologic response were hepatitis C virus (HCV) genotype 2 (odds ratio 5.66; 95% confidence interval 1.88-17.01), HCV genotype 3 (odds ratio 5.23; 95% confidence interval 1.84-14.84) and lower basal ferritin levels (odds ratio 0.99; 95% confidence interval 0.993-0.998). Independent predictors of sustained virologic response were HCV genotype 2 (odds ratio 19.54; 95% confidence interval 2.29-166.41) and HCV genotype 3 (odds ratio 3.24; 95% confidence interval 1.10-9.58). Rapid virologic response was by itself predictive of sustained virologic response (odds ratio 40.90; 95% confidence interval 5.37-311.53).'] Does post-load insulin resistance predict virological response to treatment of chronic hepatitis C patients without the metabolic syndrome?