In a randomized prospective study, 15 patients with an intracerebral haematoma caused by an intracranial aneurysm were treated concervatively and 15 operated on as an emergency. Mortality was 12/15 (80%) in the conservative group and 4/15 (27%) in the surgical group. The difference is statistically significant. The deaths in the conservative group were caused by both the primary haematoma and rebleeding. The results suggest that intracerebral haematomas caused by rupture of an intracranial aneurysm should be evacuated immediately, and that the aneurysm should be clipped at the same operation.