In one year, cerebral angiograms were performed for intracranial haemorrhage (ICH) on 334 patients. No cause for haemorrhage could be identified in 41 (12%), 30 of whom had predominantly subarachnoid (SAH) and 11 predominantly parenchymal haemorrhage (PH). These patients were prospectively examined by cranial MRI 1-6 weeks after the ictus. The MRI studies were positive in 7 patients (17%). In the 30 patients examined after SAH, 2 studies were positive, showing an aneurysm in one case and a brain stem lesion of uncertain aetiology in the other. In those examined after PH, cavernous angiomas were shown in 2, a tumour in 1 and a vascular malformation in another; useful diagnostic information was thus obtained in 36% of this group.