Cranial vena cava syndrome is an uncommon but easily recognized sequela to obstruction of the cranial vena cava. Clinical signs are characteristic-symmetric, nonpainful, pitting edema of the head, neck, and forelimbs. Causes include thrombosis of the vessel along with compression or invasion by tumors and granulomas. Evaluation typically includes thoracic imaging and tissue sampling of masses for cytologic or histologic diagnosis. Treatment is aimed at correcting the underlying process; however, endovascular therapies currently used in human medicine may apply to veterinary patients. The prognosis reflects the underlying etiology and is therefore generally guarded.