The availability of more reliable assays made infections caused by hepatitis C virus (HCV) emerging as an extremely common and insidiously progressive disease. Since 1993, in 51 out of 798 patients admitted to Department of Infectious Diseases with acute hepatitis, HCV was diagnosed as a causative agent. Seventy one percent of acute hepatitis C cases were hospital associated and city residents represented the majority of all cases. The epidemiological data and clinical course of acute hepatitis C was analysed and compared with acute hepatitis B. The frequency of acute hepatitis C increased during last 3 years in Białystok region. The clinical course of acute hepatitis C was generally milder than acute hepatitis B, with lower aminotransferases activities and bilirubin level.