The nucleus basalis of Meynert (nbM) is the single major source of cholinergic innervation of the entire cerebral cortex. Data from human and animal studies suggest that brain cholinergic activity diminishes as a consequence of aging. The aim of this study was the description of the morphological changes in the nbM in normal aging. Our cases, who died of non neurological diseases and without dementia, were divided into three comparison groups on the basis of age at death; the young group (A)--10 brains of patients (mean age mean = 34.7), the mature group (B)--15 (mean = 55.2), the old group (C)--18 (mean = 75.0). Lipid affinity was characteristic of neurons of the nbM. It occurred in young cases and reached maximum in the mature age. Astrocytic gliosis (increase in GFAP-positive astrocytes) dominated in the group B and decreased in the group C. Fibrillary gliosis showed significant positive linear correlation with age (p < 0.001). The markable feature of the aging is significant cell loss in the nbM in association with advancing age (p < 0.05). The cellular loss in the nbM which projects to entire cortical mantle may be responsible for the cortical atrophy and disorders of higher cortical function that appear during normal aging.