Several studies indicate that insulin resistance and diabetes influence sustained viral response in treatment for chronic HCV infection. We describe the case of a relapsed patient with HCV infection who achieved a sustained viral response due to an improvement in insulin resistance through modification of antihypertensive therapy. By improving insulin resistance with telmisartan, an ARB with PPAR gamma agonist propriety, sustained viral response was obtained with the same antiviral therapy. Optimization of comorbidity therapy is useful for improving the possibility of achieving a sustained viral response.