In 14 patients (eight men, six women; mean age 58 [31-72] years) with intracranial aneurysm (basilar artery in nine, anterior branches in five) the aneurysm was occluded by electrically detachable platinum coils, advanced into the aneurysm introduced via a percutaneously introduced catheter system, under local anaesthesia and fluoroscopic control. Ten patients had acute subarachnoid haemorrhage (stage II-IV). In two patients several sessions were required before complete occlusion was achieved. In one patient, with a basilar artery aneurysm, the aneurysmal wall was perforated (angiographically demonstrated contrast-medium extravasation), but this remained clinically asymptomatic. There has been no recurrence or renewed bleeding during a follow-up period of 6-12 months. The method is a highly promising addition to the micro-neurosurgical treatment of such aneurysms. However, as long-term results are still awaited, indications for using the method should be strict and only those patients should be so treated in whom operation would be associated with a high risk or who are inoperable.