A four-month-old, intact female, Greyhound-cross dog was presented with history of weight loss, lethargy and intermittent vomiting. Abdominal ultrasound revealed microhepatia, reversed position of the kidneys, polysplenia and suspicion of extrahepatic portosystemic (portoazygos) shunt. CT angiography confirmed the visceral anomalies and showed a left-sided azygos vein continuation of an interrupted caudal vena cava, associated with an extrahepatic portosystemic (portocaval) shunt. The extrahepatic portosystemic shunt was surgically corrected, and the dog had uneventful recovery. CT angiography was imperative in evaluating the characteristics of vascular anomalies and determining the required surgical correction in this complex case.