The purpose of this article is to report a case of giant pseudoaneurysm of the left superior gluteal artery that resulted after an orthopedic surgeon took a bone graft from the left iliac bone. This pseudoaneurysm was treated with arterial embolization. A bulging mass at the left buttock was noted by the patient a week after the surgery and was diagnosed as hematoma by the surgeon. The pain became severe that the patient could not remain in a supine position. CT findings of a well defined enhancing mass at the left gluteal area was confirmed by selective angiography as a pseudoaneurysm of the left superior gluteal artery. Superselective therapeutic embolization using a 3 mm coil spring emboli was carried out. Immediate relief of the symptoms was noted after successful coil embGlization. Follow-up CT scan revealed thrombus formation at the pseudoaneurysm. We therefore conclude that there is a high index of suspicion of pseudoaneurysm in a patient with an enlarging mass noted after surgery. Angiography must be performed to confirm the diagnosis. Coil spring embolization is an effective method in the management of a pseudoaneurysm.