We carried out an autopsy survey on 198 brains of Nigerians aged 40 years and above to determine the occurrence of (neuropathognomonic) changes of Alzheimer's disease (AD) in our elderly patients. Forty five patients (23%) were above 65 years of age. Appropriately stained histological sections of various parts of the brains showed mild cortical neuronal loss and absence of neurofibrillary tangles, senile plaques and amyloid angiopathy--hallmarks of Alzheimer's disease and ageing reported in the Caucasians and Japanese.