Endoscopic retrograde cholangiography and pancreatography was performed in seven healthy Beagles to assess the common bile duct and the accessory pancreatic duct after retrograde filling with an iodine contrast medium. All dogs had a major and a minor duodenal papilla. One Beagle had additionally an accessory papilla. The diameter of the contrast filled ducts was measured at three defined measure points (MP1-3) in ventrodorsal radiographs and left lateral radiographs. In ventrodorsal radiographs of endoscopic retrograde cholangiography the common bile duct had a straight craniomedial course. The mean duct diameter was from proximal to distal 3.04 +/- 1.89mm at MP1, 2.38 +/- 1.23 mm at MP2, and 2.11 +/- 0.84 mm at MP3. In ventrodorsal radiographs of endoscopic retrograde pancreatography, the left and right branch of the accessory pancreatic duct united in the pancreatic body. The mean diameter of the right branch was 0.88 +/- 0.14 mm at MP1, 0.72 +/- 0.2 mm at MP2 and 0.61 +/- 0.11 mm at MP3. The left branch had a diameter of 0.93 +/- 0.28 mm at MP1, 0.86 +/- 0.21 at MP2, and 0.6 +/- 0.07 mm at MP3. The mean length was 81.6 +/- 14.3 mm for the right and 107.0 +/- 24.9mm for the left branch. In left lateral radiographs of endoscopic retrograde pancreatography, it was not possible to differentiate the left from the right branch. Both branches ran nearly parallel and showed similar diameters but slight differences in length. The study proves that endosopic retrograde cholangio-pancreatography is possible in dogs. Radiographs taken from dogs in dorsal recumbency allow an objective assessment of the common bile duct and the accessory pancreatic duct.