Since the International Subarachnoid Aneurysmal Trial, endovascular coiling has been increasingly used as primary treatment option for ruptured or unruptured aneurysms that are feasible for coiling. To evaluate the feasibility and clinical and angiographic outcomes of coiling for unruptured middle cerebral artery aneurysms. The records of 70 consecutive patients with 76 unruptured middle cerebral artery aneurysms who underwent coiling were retrospectively evaluated. Thirty-one aneurysms were treated by single-catheter, 18 by multicatheter, 11 by balloon-assisted, 13 by stent-assisted, and 3 by a combination of multicatheter and balloon-assisted techniques. Coiling was accomplished in 75 but failed in 1 aneurysm. One patient died of consequences of subarachnoid hemorrhage occurring 9 hours after coiling. One intraprocedural aneurysm rupture occurred, which was controlled by further coil insertions and left no sequelae. There were 1 cortical infarction and 1 basal ganglia infarction, both of which recovered completely. Treatment-related permanent morbidity and mortality rates were 0% and 1.4%, respectively. Postembolization control angiography revealed 40 complete, 30 neck remnant, and 5 incomplete occlusions. Clinical follow-up was available in all patients (mean, 25 months; range, 7-105 months). There was no subarachnoid hemorrhage during follow-up, but 1 death resulting from acute myocardial infarction occurred 3 months after coiling. None of the surviving patients had any neurological deterioration. Follow-up angiography was available in 69 aneurysms at 6 to 24 months (mean, 12 months). Three major and 6 minor recurrences were detected. All 3 major recurrent aneurysms were re-treated by coiling without any complications. Most unruptured middle cerebral artery aneurysms could be safely treated by coiling with acceptable short-term to midterm outcomes. Our results warrant further study with a longer follow-up period in a larger population.