Endoscopic retrograde cholangio-pancreatography is a combination of endoscopy and fluoroscopy used for radiographic imaging of the biliary and pancreatic ducts. In order to assess its feasibility and to describe abnormal findings in dogs, this technique was performed in 30 dogs with nonspecific chronic gastrointestinal disturbances. Using an 11-mm side-view endoscope, retrograde cholangiography was successful in 20/30 dogs (67%) and pancreatography in 21/30 (70%). Success was affected by intraduodenal food, mucus or blood, problems in papillary cannulation, stomach overdistention, body size, and changes in duodenal mucosa. It was impossible to perform the procedure in dogs weighing <10 kg with the available material. Endoscopic retrograde cholangiography revealed findings that differed from previous reports in healthy beagles in 5/20 dogs. Findings included enlarged common bile duct (n=2), intraductal filling defects (n=2), and deviated course of common bile duct (n=1), and major papilla stenosis (n=1). In the dog with major papilla stenosis and intraductal filling defects, endoscopic guided sphincterotomy was performed. Endoscopic retrograde pancreatography revealed an abnormal course of the accessory pancreatic duct in 2/21 dogs. In both dogs with proven end-stage pancreatic acinar atrophy, the left duct branch did not run distal the stomach to the left but went parallel to the right duct branch and the duodenum. Repeated clinical and laboratory examinations revealed no signs of complications after endoscopic retrograde cholangio-pancreatography. It was concluded that this imaging technique is promising for the diagnosis of biliary and pancreatic diseases in dogs. It also offers the chance for new treatment options such as endoscopic guided sphincterotomy in dogs.