Acute hepatitis C is symptomatic only in 15 to 20%.We described 2 cases which clinical manifestation and results of laboratory tests (high biochemical activity)indicated acute liver damage.An operation was made two month before hospi- admission in both cases.HCVAb and HCV-RNA were found in serum of these patients.Infection of HAV,HBV,CMV,EBV, metabolic diseases and autoimmune process were excluded. Due to histopathology changes in liver tissue taken in the second week of hospitalization and to clinical manifestation,we diagnosed acute hepatitis C.The interferon therapy was started.After seven days of treatment the patient no.2 showed a test result,which had been made 5 years earlier and which ascertained a presence of HCVAb in serum.Therefore,the diagnosis in that case was changed to chronic hepatitis C. Interferon with ribavirin was applied and time of the treatment was prolonged up to one year. Morphological changes characteristic for acute hepatitis C can lead to overdiagnosis of this disease.