In a model developed to study acute pancreatitis in the dog, the disease process was comparable with the spontaneously occurring disease. Infusion of oleic acid into the accessory pancreatic duct induced, grossly and microscopically, acute hemorrhagic pancreatitis with pancreatic atrophy, fibrosis, fat necrosis, and edema. Clinical changes included persistent fever and tachycardia in all dogs and abdominal pain, vomiting, and diarrhea in most. Serum amylase and lipase activities increased markedly as did activities of alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase. Hematologic alterations included hemoconcentration (despite intensive fluid therapy) and leukocytosis due primarily to neutrophilia and monocytosis. Neither corticosteroid nor anticholinergic therapy begun 24 to 32 hours after oleic acid infusion altered the course of the disease. Dogs survived 8 days and appeared clinically normal when the study was terminated.