A five-year-old, female Great Dane dog with edema, localized trauma, mild pain, and lameness of the right hind limb was referred to the Veterinary Medical Teaching Hospital of Chungbuk National University. This dog had a history of mammary tumor excisions 6 months ago. Abnormal changes were not seen in the values of complete blood count and serum biochemical tests. But pedal direct lymphangiography using aqueous-based radiographic agent showed the obstructed lymph flow in right popliteal lymph node. Based on these observations, the dog was suspected as lymphedema resulted from lymph drainage flilure without any other possibilities of inflammation or other causes. Although recommended chemotherapy and physiotherapy had been applied for resolvinr presented problems for one month, there was no improvement on edema of damaged region and any other clinical signs. Therefore, the necropsy was performed after euthanasia under agreement of the owner of patient. In histopatholofical examination, the most characteristic lesions in the mass of femoral region were diffuse edema fibrosis and neoplastic cells in the lymphatics. Also, the neoplastic cells were very similar to those found in the tumor mass of mammary gland, which had diagnosed as fibrosing carcinoma. These facts suggested that the cause of obstructed lymph flow was the neoplasia in lymphatics of the right hind limb. With these results, a diagnosis of malignant lymphedema was made in this dog.