Aortic occlusion is a rare vascular disorder in the dog. This report describes the clinical feature of an aged Boxer with complete occlusion of the abdominal aorta caused by an intraluminal thrombus. Angiography evidenced a collateral circulation, represented by the internal thoracic artery, the cranial epigastric artery and the caudal epigastric artery, providing adequate blood flow to the pelvis and pelvic limbs. This vascular network has only recently been recognised as one of the major collateral pathways for arterial blood supply to the pelvis and lower extremities in humans with chronic aorto-iliac occlusive disease (CAOD). Furthermore, a femoral artery Doppler waveform, characterised by low amplitude, a monophasic systolic wave with blunted parabolic flow profile and a small spectral window, peculiar to humans with CAOD, is documented for the first time in a dog with aortic occlusion.