Viral hepatitis C is a serious world-wide problem. The number of infected subjects is increasing despite intense preventive measures, in particular in conjunction with the increasing prevalence of drug abuse. The extreme variability of the genome of this virus has not only epidemiological and diagnostic consequences , but in particular clinical ones. The authors present a review of recent findings regarding the genome structure of the hepatitis C virus , classification of genotypes and subtypes and their geographic distribution. The subject of interest is in particular the relationship between the genotype and clinical course of the disease, incl. therapeutic consequences. The authors discuss also the importance of genotypic variants for the development of a vaccine against hepatitis C.

        Key words: viral hepatitis C – genotypic variability – genome – genotype classification