Cerebral amyloid angiopathy is characterised by the presence of protein deposits in the wall of the cerebral vessels. Sporadic forms with deposits of Abeta peptide are the most frequent. The diagnosis of cerebral amyloid angiopathy is only certain when amyloid deposits can be visualized on cerebral tissue by biopsy, that appears in most circumstances to carry too many risks for the expected benefits, or post mortem. The clinical diagnostic criteria are advanced age, morphology of the intracerebral hematomas, occurrence of several episodes of intracerebral haemorrhages and presence of dementia. Recent progresses in the field of MRI make the diagnosis of cerebral amyloid angiopathy easier and more accurate. MRI should be more frequently performed in aged patients.