A retrospective postmortem analysis of 25 cases of cerebral amyloid angiopathy (CAA) in the setting of Alzheimer's disease or senile dementia of the Alzheimer type (AD/SDAT) is reported. Seven patients experienced clinically significant cerebral infarcts or hemorrhages or both. There was no statistically significant difference in the incidence of infarcts or hemorrhages in hypertensive and nonhypertensive patients. Hypertension does not appear to be an additional risk factor in the causation of cerebral infarct or hemorrhage associated with CAA in the setting of AD/SDAT. Just over half of patients with CAA and significant ischemic and/or hemorrhagic brain lesions showed atherosclerosis of the circle of Willis, sometimes in the context of severe disseminated atheromatous disease.