We had two cases of hepatitis developing after surgery. Case 1. A 47 year old male underwent surgery for amputation of the lower leg under enflurance anesthesia. Preoperative liver function test were slightly abnormal. On the 25th portoperative day, serum transaminases were elevated and the A/G ratio was reversed. On the 65th postoperative day, the liver function tests returned to near normal leve. Case 2. A 37 year old male underwent the first surgery for reduction of a pateliar fracture under spinal anesthesia. Preoperative serum transaminages were elevated and other laboratory findings at normal levels. On the 20th postoperative day serum transaminases were more elevated and on the 120th postoperative day, ti became normal again. This patient underwent the second surgery for removal of a K-wire under enflurane anesthesia and afterwards hepatitis recurred. On the 60th 2nd postoperative day LEFs became nearer to normal level and he was discharged in good health. Possible causes of the hepatitis in these cases were considered to be the preoperative liver disease, blood transfusion, the stress of the surgery and anesthesia.