Endovascular coil embolization has been a major treatment modality for unruptured intracranial aneurysms (UIAs) in South Korea. However, there are still few reports on the outcomes of this procedure. We performed a retrospective, multicenter study to determine how safe and effective coiling for UIA has been over the most recent 3years in South Korea. We analyzed a total of 2,180 UIAs in 2,035 patients who were treated by coiling from January 2007 to December 2009 at 22 centers in South Korea, with a focus on patient characteristics, the location and size of the aneurysms, procedural complications, and angiographic and clinical outcomes. Coiling was successful in 98.0% of the cases (2,137/2,180 aneurysms). Immediate post-procedural angiography demonstrated complete occlusion in 62.6% (1,337/2,137 aneurysms), residual neck in 32.4% (692/2,137), and residual sac in 5.0% (108/2,137) of the cases. The rate of any procedure-related adverse event was 6.9% (148/2,137 aneurysms). The rates of permanent morbidity and mortality were 1.8% (39/2,137 aneurysms) and 0.1% (2/2,137 aneurysms), respectively. Follow-up conventional angiography or MRA at ≥6months was performed in 85.7% (1,832/2,137 aneurysms) of cases. Among the eligible aneurysms for follow-up angiographic analysis, major recanalization was noted in 3.9% (72/1,832 aneurysms, mean follow-up interval, 12months). Among these, 68 aneurysms (3.7%) were re-treated. An aneurysm of the middle cerebral artery (MCA) was a risk factor for incomplete occlusion (P = 0.049) and major recanalization (P = 0.046). During follow-up, no aneurysmal rupture occurred. Endovascular coil embolization of UIAs has been an effective preventive modality with low procedure-related morbidity in South Korea.