Postoperative jaundice is an occasional complication of major surgery. Four illustrative cases are described and a mechanism of development is suggested. The jaundice may seem to be biochemically of the obstructive type. Most of the bilirubin is of the conjugated type. The disturbance of liver function can be caused by several factors, including massive transfusion, hematoma in tissues, shock, heart failure, anoxia, infection and perhaps medications. Postoperative jaundice by itself is not of cardinal importance in deciding the prognosis of the patient.