Morphometric parameters of "neuron-capillary-glia" system, succinatedehydrogenase (SDG), NAD-diaphorase and lipid peroxidation (LPO) activities were studied in area 41 and area E of human cerebral hemisphere cortex. It was established that the aging was associated with a reduction in a portion of capillaries, decline in neuronal SDG activity and an activation of LPO. The consequences of these phenomena are the death of some part of neurons accompanied by a substitutive gliosis and an increase of glial index. Augmentation of both volumetric parameters of capillary bed and neuronal NAD-diaphorase activity, presumably, represents the compensatory reaction in human cerebral cortex in senile age. The changes described above were found to be more pronounced in auditory cortex (area 41) than in olfactory cortex (area E).