The development of this guideline was initiated and coordinated by the Netherlands Association of Gastroenterologists and Hepatologists (Nederlandse Vereniging van Maag-Darm-Leverartsen). The aim is the establishment of practical guidelines in the evaluation and antiviral treatment of patients with chronic hepatitis C virus (HCV) infection. This includes recommendations for the initial evaluation of patients, the choice and duration of antiviral therapy and the follow-up after antiviral therapy. Hepatitis C is a slowly progressive disease. The initial evaluation of chronically HCV-infected patients should include liver biochemistry testing, virological testing and abdominal ultrasound imaging. Liver biopsy is no longer a routine procedure. Antiviral treatment should be considered for all HCV-infected patients. Current antiviral treatment is a long-term process and is associated with substantial side effects. When deciding whether to start treatment or not, the chance of successful treatment (80% with hepatitis C genotype 2 and 3 and 50% with hepatitis C genotype 1 and 4), the fibrosis stage, the expected side effects and the compliance of the patient should be taken into consideration. In the absence of significant fibrosis and necroinflammation in liver biopsy, postponing treatment is an option. Current antiviral treatment is contraindicated in patients with Child-Pugh-class B or C cirrhosis. The possibility of a liver transplantation should be investigated in these patients. Significant comorbidity with a limited life expectancy is an absolute contraindication for antiviral treatment Treatment of chronic hepatitis C consists of administration of peginterferon and ribavirin for 24 or 48 weeks. Patients with hepatitis C genotype 1 or 4 are treated for 48 weeks. Patients with hepatitis C genotype 2 or 3 are treated for 24 weeks. In patients with undetectable HCV RNA after four weeks (28 days) of treatment, a shorter treatment is equally effective (12 to 16 weeks for hepatitis C genotype 2 or 3; 24 weeks for hepatitis C genotype 1 or 4). Outpatient clinic visits are recommended at the start and after 2, 4, 8, and 12 weeks of treatment, and thereafter every four to six weeks until the end of treatment. It is recommended to stop treatment if the HCV RNA level has not decreased by at least 2 log10 IU/ml (c/ml) after 12 weeks of treatment or when HCV RNA is still detectable after 24 weeks of treatment. The recommended frequency of outpatient clinic visits for patients who are not being treated is once every six months in patients with cirrhosis, otherwise every 12 months. It is expected that new anti-HCV-medication (STAT-C, specifically targeted antiviral therapy for HCV) will become available in the near future. Therefore treatment of chronic HCV infection will probably be more effective in the future.