We present a case of an unruptured, large, complex, middle cerebral artery trifurcation aneurysm that was successfully treated by selective occlusion of the neck with a single, newly available UltraSoft coil. The satisfactory initial anatomic result was stable, as demonstrated on a 3-month follow-up arteriogram that indicated complete anatomic cure. The novel UltraSoft coil offers additional possibilities in the endovascular management of difficult-to-treat vascular lesions.