A nine-year-old male neutered Greyhound presented to the Cornell University Hospital for Animals on October 17, 2018 for a 3 month history of progressive hind end weakness. The patient had a history of acute tetraplegia and ataxia in January 2018 and was suspected of having a stroke. He underwent general anesthesia for a periodontal treatment in July 2018, after which clinical signs began to emerge. Physical exam on presentation revealed several small fatty nodules on the ventrum, kyphotic posture, short-strided gait, consistent offloading of the hind limbs, caudal lumbar spinal pain, subjectively decreased hindlimb muscle mass, and limited flexion of the right carpus. Spinal reflexes showed decreased cutaneous trunci response at the right L2 and left L3, reduced patellar reflexes bilaterally, and questionably reduced tail tone. Additional diagnostics revealed a thrombocytopenia and lymphocytosis, renal azotemia, hypernatremia, hypokalemia, hypophosphatemia, and elevated AST, amylase, and creatine kinase. However, some of these abnormalities may be normal for Greyhounds. Snap test was negative for tick-borne diseases. Disseminated intravascular coagulation (DIC) panel revealed normal D-dimers and fibrinogen levels. Urinalysis of free catch urine revealed 3+ proteinuria, a urine specific gravity (USG) of 1.046 and a large amount of blood. Abdominal ultrasound revealed a large, medium echoic thrombus occupying approximately 90-95% of the aortic lumen immediately cranial to the aortic trifurcation. In the left external iliac artery, the thrombus occupied the majority of the lumen, extending distally to just proximal to the vascular lacuna at which point it terminated. The thrombus occupied the majority of the lumen of right external iliac artery extending the length of the artery and into the femoral artery to the level of branching into the distal caudal femoral and popliteal arteries. Both kidneys contained hypoechoic lesions and mottled, hyperechoic cortices with decreased corticomedullary distinction. A focal echocardiogram was normal and there were no significant findings on thoracic radiographs. The clinical signs, blood work results, and especially abdominal ultrasound findings were indicative of aortic thromboembolism. The patient was started on antiplatelet therapy and continued to do well at his two-week recheck. This presentation will discuss the physical exam findings, diagnostic tests, possible etiologies, treatments, and pathophysiology of aortic thromboembolism.