Serum levels of carbohydrate antigen (CA) 19-9 exceeding 1000 U/mL are considered highly specific for pancreatic cancer and have not been reported in nonmalignant pancreatic disease. A young man with obstructive jaundice, a serum CA 19-9 level of 2350 U/mL and a mass in the head of the pancreas, seen on computed tomography, was found to have chronic pancreatitis without malignant disease. This case demonstrates that a markedly elevated serum level of CA 19-9 can occur in nonmalignant pancreatic disease and emphasizes the need for a histologic diagnosis of malignancy even if the clinical diagnosis of pancreatic cancer seems certain.