PURPOSE To present a rare case of complete persistent sciatic artery aneurysm successfully treated by coil embolization and to suggest a new classification for this anomaly that encompasses both clinical and pathological factors. METHODS AND RESULTS A 77-year-old female presented with sudden onset of sharp, throbbing left thigh and foot pain. A nontender 10.0- x 7.0-cm pulsatile mass was found over the inferolateral aspect of the left buttock on examination in the right lateral decubitus position. Angiography demonstrated a 6.9-cm sciatic artery aneurysm with the distal sciatic artery completely thrombosed. Before planned bypass grafting, the aneurysm and distal segment of the internal iliac artery were successfully embolized with coils through a left percutaneous approach. The patient's symptoms resolved with no deterioration in limb perfusion, and further revascularization was unnecessary. Postembolization imaging showed complete occlusion of the aneurysm, which has continued for 19 months. CONCLUSIONS The application of endovascular techniques and surgical revascularization procedures provides numerous management options for the treatment of an aneurysmal persistent sciatic artery. This case demonstrates that clinical evaluation between staged procedures may obviate the need for further intervention.