Résumé : The exocrine function of the pancreas studied through the duodenal drainage (DD) and through the pure pancreatic juice collection (PPJ) has been correlated with the duct's morphology obtained via endoscopic pancreatography for patients with chronic pancreatitis. The diagnosis of chronic pancreatitis was assessed on clinical and radiological grounds and the patients were classified in 4 grades of severity related to the abnormalities of the pancreatography. The volume of the secretion and the concentrations and outputs of bicarbonate and amylase after secretin-pancreozymin stimulation have been recorded. A discriminant analysis permitted to ponder and to combine on a linear way the useful parameters. For the DD, the maximal bicarbonate concentration combined with the maximal amylase output allows a correct classification for only 46 % of the patients. On the other hand, the maximum bicarbonate output and the maximum bicarbonate concentration in the PPJ after secretin is the most discriminant combination, providing the best (70 %) correspondance to the morphologic classification. This mathematical analysis of the PPJ electrolytes has the advantage to provide a linear evaluation of the pancreatic exocrine function, which is complementary to the pancreatography in the diagnosis of chronic pancreatitis. © 1985 Springer-Verlag.