The transmission of hepatitis C virus (HCV) by direct percutaneous exposure to blood is well documented by both epidemiological and experimental studies. Persons commonly considered at increased risk of acquiring HCV include blood and blood product recipients, parenteral drug users and health-care workers. These groups, however, only account for half of the hepatitis C cases reported, and many cases of HCV infection associated with nonparenteral routes have been reported but there have still remained controversy, and the epidemic outbreak of hepatitis C through nonparenteral routes have been reported extrernely rarely in the world. Most of epidemiologic studies of the hepatitis C had been reported before the developement of the various diagnostic tools such as anti-HCV test, detection of HCV RNA using polymerase chain reaction and direct genomic sequencing. These newly developed diagnostic methods may open the new era of the hepatitis C and the remained controvery is expected to be solved in the near future. We report the epidemic outbreak of hepatitis C in 13 cases in Nam-Chang-Lee from April to October in 1989. On epidemiologic studies, no case had identifiable parenteral transmission routes. The monthly incidence shows unimodal and highly comprewed pattern suggesting that this outbreak was transmitted within a short period and through the same transmission route, possibly nonparenter- al route. The diagnosis of the hepatitis C was made by the anti-HCV (positive rate: 81.8%) and the detection of the HCV genome. The genomic sequences of N51 region of the isolated two cases showed 84-96% homology to the Japanese type and 87-98% to the Taiwan type but only 70-71% to the prototype. This study may suggest the evidence of epidemic outbreak of hepatitis C transmitted via nonpar-enteral route. But further epidemiologic characterizations of this epidemic may provide insight into the routes of' HCV transmission and further studies are required to determine the clinical significances of different types of HCV.