The findings from endoscopic retrograde pancreatography (ERP) and secretin-CCK test data were compared in 69 patients: 36 with chronic pancreatitis, 9 with possible chronic pancreatitis, and 24 without chronic pancreatic disease. The ERP findings were also compared with the histologic changes in pancreatic tissue in 18 patients who underwent pancreatic surgery for chronic pancreatitis. ERP films were reviewed according to the criteria proposed by Kasugai et coll. with special attention paid to the side branches. Secretin-CCK test data were interpreted using the discriminant analysis. A good correlation between bicarbonate and chymotrypsin output and ductular changes at ERP was found. The results of ERP and the secretin-CCK test were compatible in 86 per cent of the patients. The relationship between ERP findings and histologic changes was not straightforward. It was concluded that ERP and the secretin-CCK test are complementary in the diagnosis of chronic pancreatitis. ERP does not necessarily represent the histology in chronic pancreatitis.