Background: Some degree of recanalization is reported in up to one-third of intracranial aneurysms treated with endovascular coiling. A technical development potentially effective in avoiding recanalization is the Matrix Detachable Coil (MDC), which is covered with a biodegradable polymeric material that enhances intra-aneurysmal clot organization and fibrosis. Purpose: To report the initial clinical experience of MDC for endovascular aneurysm coiling in a single-center, single-operator, and well-defined population setting. Material and Methods: 118 aneurysms in 104 patients (73 with subarachnoid hemorrhage, SAH) were embolized with MDC alone (n=52) or combined with bare platinum coils (n=66). Results: Initial aneurysm obliteration was class 1 (complete obliteration) in 45 aneurysms (38.1%), class 2 (residual neck) in 44 (37.3%), and class 3 (residual aneurysm) in 29 (24.6%). Procedure-related morbidity was 4.8%, and mortality 0.96%. Clinical follow-up of 61 patients with SAH (mean 5.9 months, range 1-17 months) showed good outcome (Glasgow Outcome Scale, GOS 4-5) in 39 (63.9%), and poor outcome or death (GOS 1-3) in 22 (36.1%). Imaging follow-up of 73 aneurysms (average 6.5 months, range 1-17 months) showed class 1 in 47 (64.4%), class 2 in 18 (24.7%), and class 3 in eight (10.9%). Recanalization occurred in 11 aneurysms (15%), of which four (5.5%) required re-treatment. Conclusion: This study confirms that aneurysm coiling with MDC is feasible, effective, and safe. © 2007 Taylor and Francis.