An 11 year spayed domestic shorthair cat was presented to the Emergency Service at the Cornell University Hospital for Animals with a four day history of lethargy, inappetance, fever, and a recently elevated total bilirubin and alanine aminotransferase (ALT). The patient was tachypneic, mildly jaundiced and had significant abdominal pain with a palpable mass in her cranial abdomen. Point-of-care blood work revealed an anemia with icteric serum and a low ionized calcium. A presumptive diagnosis of acute pancreatitis was made, based primarily on abdominal ultrasonographic findings. Supportive treatment was initiated including analgesia, anti-emetics, IV fluids, enteral nutrition via a nasogastric tube, vitamin supplementation, and broad spectrum antibiotics. The patient's condition improved significantly over her three-day hospitalization, and she was eventually discharged to the care of her owner. This paper will discuss the pathophysiology, diagnosis, and treatment strategies of acute pancreatitis in the feline patient.