The mean +/- S.E.M. ratio of amylase to creatinine clearance significantly increased at 24 hours after operations on the stomach and gallbladder but not after operations at sites remote from the abdominal cavity. Clinically, the elevated amylase to creatinine clearance ratio was not accompanied by pancreatitis. In dogs, surgical handling of the pancreas alone caused a significant increase in this measurement. The amylase to creatinine clearance ratio is not likely to be helpful in predicting the rare, but serious, postoperative complication of pancreatitis.