Background: Pylephlebitis, a rare complication of abdominal infections, is a septic thrombophlebitis of the portal venous system with high rates of morbidity and mortality. Case Report: We present a case of pylephlebitis complicating acute appendicitis and report the utility of a computed tomography scan in the diagnosis. Why Should an Emergency Physician be Aware of This?: The prompt diagnosis and appropriate treatment of pylephlebitis are crucial to reduce morbidity and mortality, but clinical presentation is often nonspecific. A computed tomography scan is instrumental in the early diagnosis of pylephlebitis because it readily reveals the thrombus in the mesenteric or portal vein in the setting of acute appendicitis. Early and aggressive treatment with broad-spectrum antibiotics is necessary, and anticoagulation therapy can also be used to prevent bowel ischemia. (C) 2016 Elsevier Inc.