A 4-year-old female miniature pincher with a 40-days history of weight loss, lethargy and vomiting was referred to Small animal hospital, Faculty of veterinary medicine, University of Tehran. The case also had severe jaundice, chronic diarrhea and steatorrhea. All of the efforts for saving the life of the case were not successful and finally the signs deteriorated and animal died because of hypovolemic shock and electrolyte imbalances. At necropsy, the body was cachectic, edematous and severely icteric. A bloody ascetic fluid, lacking fibrin strands was also noticed in the abdominal cavity. Firm tumor masses originated from pancreas were seeded to peritoneum with multiple attachments to duodenum. There were also some points of metastasis in regional lymph nodes and liver. On the basis of histopathologic characteristics of the tumor, the mass was diagnosed as relatively well-differentiated exocrine pancreatic adenocarcinoma.