Infections with the hepatitis C virus (HCV) are pandemic, and the WHO estimates a world-wide prevalence of 3%. In Middle Europe approximately 1% of the population are infected, mostly with genotype 1 (85% in Austria). Since the discovery of HCV in 1989 and the introduction of the HCV antibody test in 1990, mainly chronic asymptomatic cases were diagnosed. In developed countries, chronic hepatitis C is the most prominent cause for liver cirrhosis, hepatocellular carcinoma, and liver transplantation. In former years, transmission of HCV was predominantly iatrogenic, e.g. by blood transfusions before 1990, blood products such as coagulation factors in hemophiliacs or anti-D-globuline in rhesus incompatibility, parenteral anti-schistosomal treatment in Egypt, contaminated endoscopes or cardiac surgery. Today, sporadic transmission is more prevalent, mostly in drug addicts via needle sharing, and seldom by needle-stick injuries in medical personnel, vertical transmission from mother to baby, tattooing, piercing, or razor sharing. Given the lack of a prophylactic HCV vaccine, preventive measures are very important such as screening of blood products by PCR, use of disposable instruments. or procurement of drug addicts with single-use syringes and needles.