Middle cerebral artery (MCA) aneurysms often have unfavorable anatomical characteristics preventing successful endovascular occlusion. We reviewed the outcomes of our series of endosaccular embolization of MCA aneurysms using bare platinum coils, angiographic images, and medical records. Immediate and follow-up angiographic results were categorized as complete occlusion, residual neck, and residual flow. Follow-up angiographic changes were categorized as unchanged, minor or major recurrence, and progressive thrombosis. Between December 2001 and August 2007, 112 patients with 113 MCA aneurysms underwent endovascular treatment, of whom 60 presented with subarachnoid hemorrhage (SAH) due to MCA aneurysm rupture. Immediate angiographic outcomes for 103 aneurysms revealed complete occlusion in 64, residual neck in 21, residual flow in 18, and failed embolization in 10. Follow-up angiography of 70 aneurysms demonstrated 41 unchanged, 10 minor recurrences, 12 major recurrences, 7 progressive thromboses, and no bleeding of coil embolized aneurysms. Outcomes of 58 SAH patients treated endovascularly revealed 45 good recovery and moderate disability, 10 severe disability or persistent vegetative state, and 3 deaths. Forty-four of the 45 patients with unruptured aneurysms treated endovascularly had no changes in their neurological status. One of 5 patients with complications had permanent morbidity. For patients with MCA aneurysms suitable for endovascular surgery, bare platinum coil embolization can be performed with acceptable low morbidity and mortality rates, with a lower risk of postprocedural aneurysmal bleeding.