Little is known about the epidemiology of chronic hepatitis C (CHC) in Germany and especially about the importance of transmission, duration of infection, genotypes, symptoms and quality of life of the patients. The current study prospectively evaluates epidemiological and clinical data of patients infected with the hepatitis C virus (HCV). Using online data entry, various characteristics of 10,326 untreated patients with CHC were documented from March 2003 until May 2006 in 352 centres all over Germany. Mean age of patients was 43.4 years. Patients infected by i.v. drug abuse were considerably younger (36.5 years) than the remaining patients (49.2 years). As indicated by their native language, 64.4% of the patients came from Germany and 19.2% from Russia. 61.7% were infected with genotype 1 and 34.9% with genotype 2 or 3. 45.5% of the patients had been infected by i.v. drug abuse. In at least 5.4% of the patients liver cirrhosis had been proved by biopsy. 63.5% of the patients felt an impairment of quality of life caused by CHC. In many patients infected with hepatitis C socio-economic issues are existent. This is reflected, i.e., in very high rates of unemployment in special subpopulations. Coinfections with hepatitis B and HIV occurred in 1.5% and 4.7%, respectively. Nearly 80% of patients were managed near their homes. The data of the 10 326 patients represent about 2% of all German patients with CHC. This database is up to now the largest of its kind and gives a representative insight into the epidemiological situation of CHC in Germany.