A 3-year-old, intact male Pungsan dog was presented for a 2-week history of a non-weight-bearing lameness of left hindlimb with anorexia. The dog had no history of trauma, and never been routinely vaccinated or treated with heartworm preventatives. The complete blood count showed severe leukocytosis and neutrophilia with left shift. Serum biochemistry showed hypoalbuminemia, azotemia, and increased hepatobilliary enzyme activity. A canine heartworm antigen test was positive. Thoracic radiographs were consistent with heartworm disease as evidences by main pulmonary artery enlargement, right-sided cardiomegaly, and interstitial lung pattern. Echocardiography revealed pulmonary valvular regurgitation and pulmonary hypertension. Selective femoral arterial angiogram was performed, and bilateral femoral arterial occlusion was identified. The dog died after angiogram, and necropsy was performed. At necropsy, adult heartworm and a large blood clot were found within the lumen of left and right femoral artery. This case report describes an unusual migration of heartworm to femoral artery that caused hindlimb lameness.