OBJECTIVES: Currently, 400-500 thousand people are suffering from Hepatitis C (HCV) in Germany (62% genotype 1). HCV is one of the leading causes for chronic liver disease. Experts have estimated that about 27% of end-stage cirrhosis and 25% of hepatocellular carcinoma are associated with HCV. Although HCV is associated with high costs, reliable data are scarce in Germany. Aim of the study was to assess the costs for treating chronically infected HCV patients in routine care. METHODS: We conducted a retrospective multicenter observational study. Design was approved by an ethics committee and patients were asked for their informed consent. Healthcare utilization was extracted from doctor files in six medical centers. Costs were calculated using official fee-scales and statistics. Societal perspective was taken. RESULTS: In total, 315 patients were analyzed. The mean age was 49.4 years, 57.5% were male and 67.9% had a genotype-1 infection. Most common routes of transmission were injection drug use (39.0%) and infection through blood products (15.9%). In 41.3% of patients route of transmission was unknown. The average total costs were €19,147 including ambulatory care (€1,686), pharmaceuticals (€14,875), inpatient care (€1,293) and sick leave (€1,293). Cost differences were observed between patients groups (mild HCV, moderate HCV and compensated cirrhosis, decompensated cirrhosis). Patients receiving a 16-week treatment had average total costs of €8,230. A 24-week treatment resulted in €13,674, 48-week treatment in €25,396 and 72-week treatment in €41,175. In nearly 30% of patients treatment duration did not correspond to official recommendations. CONCLUSIONS: Treatment of HCV patients is associated with high costs mainly affected by length of antiviral therapy. It is inevitable to follow current guidelines and monitor patients closely in order to avoid unnecessary costs. The analysis is the basis for implementing new therapies which started with the introduction of protease inhibitors in 2011.