An eight year old male castrated mixed breed dog presented for hindlimb paresis of three days duration. A diagnosis of caudal aortic thromboembolism was confirmed using color flow Doppler ultrasonography. A protein-losing nephropathy was suggested as the underlying cause due to hypoproteinemia, hypoalbuminemia, proteinuria with a urinary protein:creatinine ratio of 17.6. The anti-thrombin III level was determined to be reduced at 67%. The dog was started on low-molecular weight heparin injections and low dose-aspirin for hypercoagulability. Conjunctively he was also placed on an ACE inhibitor, 3V cap dietary supplements and Purina NF diet for treatment of his protein-nephropathy of undiagnosed etiology. The LMW heparin therapeutic dose was monitored by measuring anti-factorXa activity in the blood. Due to cost and convenience, the dog was started on oral warfarin therapy two weeks later and discontinued the LMW heparin therapy. Therapeutic monitoring was achieved by measuring the Prothrombin clotting time. Although ultrasonographically the clot has shown an increase in size both proximally and distally, the dog continues to do well at home with moderate exercise intolerance with a grade 4-5 paresis.