From January to December 1983 the author has operated on 456 intracranial aneurysms with microsurgical techniques. Most of them (74.8%) arose from the internal carotid and from the anterior comunicating artey. Subarachnoid hemorrhage was the first occurence in 92% of the patients. The favored technique was occlusion of the neck of the aneurysm with clip. The best surgical results were achieved when the patients were physical and mentally well and were operated on after a week following subarachnoid hemorrhage. The over all mortality was 6.2%.