We have investigated the relationship between cholecystokinin levels and abdominal pain in patients with chronic pancreatitis. The baseline and postprandial cholecystokinin levels were measured in 15 patients with chronic pancreatitis (8 with and 7 without abdominal pain) and in a reference group of 8 healthy subjects. The baseline, 30 and 60 min postprandial plasma cholecystokinin levels were significantly (p < 0.05) higher in the patients with pain as compared with the other two groups. No correlation was observed between increased cholecystokinin levels and impairment of the exocrine pancreatic function as assessed by the NBT-PABA test. The increased cholecystokinin levels might be an important factor in the genesis of pain in chronic pancreatitis.