We would like to present a case of pseudoaneurysm of the anterior tibial artery after closed intramedullary nailing of a tibial shaft fracture. In an automobile accident, a 56-year-old man sustained a transverse diaphyseal fracture of the left tibia. 10 days after closed intramedullary nailing with laterally inserted proximal and distal locking screws, an enlarging tender, pulsating mass was found over the anterolateral aspect of his left leg. Ultrasonography and angiography revealed a pseudoaneurysm of the anterior tibial artery at the level of the distal locking screw. Surgical resection of the injured segment of the anterior tibial artery associated with a pseudoaneurysm and a vein graft was performed.