The purpose of this study was to compare the diagnostic efficacy of endoscopic retrograde pancreatography (ERP) and secretin-CCK test for the diagnosis of pancreatic disease. The bicarbonate output after the secretin stimulation was low in 26 out of 30 patients (87%) with pancreatitis, whereas ERP revealed an abnormal duct in 21 (70%) of these patients. In all 7 patients with pancreatic carcinoma, ERP showed major abnormalities, whereas the bicarbonate output was reduced only in four of them. Thus, the secretin test appears to be at least as efficient as the ERP in disclosing pancreatitis. On the other hand, ERP seems to be a more reliable method for the diagnosis of pancreatic carcinoma.