The authors report their experience using electrolytically detachable coils for the treatment of residual cerebral aneurysms following incomplete surgical clipping. Eight patients were treated for six anterior and two posterior circulation aneurysm remnants. All patients were referred for endovascular treatment by experienced cerebrovascular neurosurgeons at the authors' institution. Patients underwent follow-up angiography immediately after endovascular treatment. In seven of the eight patients, additional follow-up angiographic studies were obtained at periods ranging from 7 weeks to 2 years posttreatment. The latest follow-up angiograms demonstrated that six of the eight aneurysm remnants were 100% occluded, with near-complete occlusion of the other two aneurysm remnants. There was no permanent neurological or non-neurological morbidity or mortality associated with the treatment. There was no incidence of aneurysm hemorrhage during or after treatment. Endovascular treatment of cerebral aneurysm remnants following prior surgical clipping can be accomplished with acceptable morbidity and mortality rates. Endovascular coil occlusion can play an important adjunctive role in the treatment of those aneurysms that have been incompletely obliterated by surgical clipping.