Cerebrovascular amyloid deposition (CVAD), caused by deposition of the beta/A4 protein, has been previously identified as a cause of cerebral haemorrhage, yet its prevalence is uncertain. The presence of vascular amyloid was studied in brains of 169 patients by immunohistochemical and Congo red staining. Fifty patients had cerebral haemorrhage (CH), 56 had cerebral infarction (CI), and 63 had neither haemorrhage nor infarction (control group). CVAD was found in 38 per cent of the CH group, 25 per cent of the CI group, and 32 per cent of the control group. The incidence of CVAD increased with age in each group. Immunohistochemical staining with an antibody to beta/A4 protein was more sensitive than Congo red staining the demonstrating the extent of vascular amyloid. Within the CH group, CVAD was present in the vessels at the site of haemorrhage in 6/8 (75 per cent) of pure superficial (lobar) cerebral haemorrhages. While amyloid was detected in vessels in the brain of 10/37 (27 per cent) of pure deep cerebral haemorrhages, none was present in vessels at the site of haemorrhage. CVAD is a common pathological finding in the elderly and has a significant association with pure superficial (lobar) cerebral haemorrhages.