The seric levels of gastrin, pancreatic glucagon, pancreatic polypeptide, enteroglucagon, motilin and cholecistokinin were evaluated in ten patients with chronic Chagas' disease and compared with those observed in nine normal control subjects. The seric values of all the hormones were determined on basal stimulation, after continuous intravenous secretin infusion and infusion of stepwise increased concentrations of caerulein (direct stimulation), and after intravenous secretin administration followed by intraduodenal instilation of increased concentrations of phenylalanina (combined stimulation). All the hormones, basal and after direct stimulation, showed similar values, except gastrin that in the chagasic group presented higher levels than in control subjects. Phenylalanine and pancreatic polypeptide showed significantly higher values in the control group than in the one of patients with Chagas' disease. The hormonal response in patients with chronic Chagas' disease suggested a neural impairment of the enteropancreatic axis.