We present our initial experience of concentric-filling technique using MicruSphere 3D coils (Micrus Endovascular, San Jose, CA) in the treatment of intracranial aneurysms. 149 intracranial saccular aneurysms in 142 consecutive patients (mean age 56.6-/+12.7, ruptured in 54 (36.2%)) were treated with the concentric-filling technique. The mean aneurysm volume was 169.0-/+363.0 mm(3). Neck remodeling technique was used in 120 (80.5%). Procedure-related problems were recorded. Initial embolization results were evaluated, and the coil packing density was calculated. Clinical and angiographic follow-ups were performed after six months. Any changes in embolization status were classified as 'improved', 'unchanged', or 'worse'. The overall packing density was 40.1% (range 10.5-90.9%). The permanent morbidity and mortality rates were 4.0% and 1.3%, respectively. The initial Raymond and Roy classification results were class 1 in 37 aneurysms (24.8%), class 2 in 50 (33.6%), and class 3 in 62 (41.6%). On the mean follow-up examination of 8.2 months in 103 patients (72.5%), there were one transient ischemic attack, one minor stroke, and one instance of rebleeding. Angiographic follow-up in 101 aneurysms (67.8%) showed the change in embolization status as 'improved' in 42 aneurysms (41.6%), 'unchanged' in 42 (41.6%), and 'worse' in 17 (recanalisation rate, 16.8%). The concentric-filling technique using Micrusphere 3D coils was effective in achieving high packing density which in turn resulted in stable embolization in the majority of the aneurysms. Longer follow-up is warranted to determine the durability of these results.