Pancreatic secretion of zinc and copper in duodenal juice were measured in 7 healthy persons and in 9 patients with chronic pancreatitis. Stimulation with cholecystokinin and secretin increased secretion of zinc in healthy persons but not in patients. Copper secretion was not influenced. In patients with chronic pancreatitis, the correlations between zinc secretion, and amylase and trypsin secretion were significant while in healthy subjects they were not. Possibly pancreatic zinc secretion in the duodenal juice might be used as a measure of exogenic pancreatic function, and determination of zinc in duodenal juice may replace enzyme determinations in the diagnosis of chronic pancreatitis.