A 57-year-old man with antithrombin III deficiency with deep vein thrombosis and pulmonary thromboembolism after surgery for colon cancer was managed with warfarin and inferior vena cava filtration. After starting chemotherapy for liver metastasis, the control of his prothrombin time-international normalized ratio in response to warfarin began to fluctuate. Warfarin was changed to edoxaban (an oral direct Factor Xa inhibitor), and he had no recurrence of venous thromboembolism or bleeding for approximately 1 year. We conclude that edoxaban could be a useful treatment option for complicated patients with deep vein thrombosis.