Background: Pancreatic exocrine dysfunction has been described frequently in IDDM and NIDDM patients. Most authors tried to explain this finding as a diabetic complication. On the other hand, diabetes secondary to chronic pancreatitis (CP) might be more common than believed so far. Aim of the Study: In this study we evaluated pancreatograms of patients with known diabetes mellitus in order to detect ductal morphology changes characteristic for CP. Methods: Consecutive diabetic patients admitted for ERCP for different reasons were evaluated retrospectively concerning ERCP findings, especially pancreatic duct changes (Cambridge classification), diabetes type, duration and therapy. Results: 156 patients (76 male, 80 female; mean age 60 years (19-93)) were studied (38 IDDM; 118 NIDDM). Pancreatic ducts were classified as normal in 23.3%, CPdegreesI in 22.7%, CPdegreesII in 32.7% and CPdegreesIII in 21.3%. The duct changes did not correlate with diabetes type (p = 0.19), diabetes duration (p=0.38), diabetes therapy (p = 0.5) or age (p = 0.48). Conclusion: Since CP should be defined by morphological and functional changes, it must be concluded that a substantial number of patients with a primary diagnosis of diabetes mellitus may have CP as a concomitant disease or, more likely, as a cause for their diabetic state. Copyright (C) 2002 S. Karger AG, Basel and IAP.