The effect of diabetes mellitus on the dynamics of neurocyte and gliacyte apoptosis intensity in the cortex of the frontal, parietal and temporal lobes of the cerebral hemispheres under conditions of ischemic-reperfusion lesion has been studied in experiments on rats. The level of apoptotic processes in the neuro- and gliacytes of the frontal cortex has been found to be unchanged after 20 minutes of carotid ischemia followed by one hour reperfusion according to the indices examined in animals with out diabetes mellitus. Apoptosis of neurocytes is activated in the cortex of the parietal lobe, and that of the neuro- and gliacytes – in the cortex of the temporal lobe. Three-month diabetes mellitus intensifies apoptosis of neurons and glial cells in the cortex of the frontal and temporal lobes, neurons in the cortex of the parietal lobe and decreases apoptosis of gliacytes in it. In early ischemic-reperfusion period the activity of apoptotic processes in the cortex of the frontal and temporal lobes does not change in animals with diabetes mellitus, but it decreases in the cortex of the parietal lobe at the expense of glial cells. On the 12th day of observation the activity of apoptotic processes in neurocytes of the cortex of the temporal lobe increases in rats without diabetes mellitus, and it decreases in the glial cells. We detected a reduced content of the protein p53 in neurons and increased density of р53+-cells. In this period of observation in rats with diabetes mellitus the activity of apoptotic processes decreases in general both in neurons and glial cells of all the lobes. The results obtained point for the availability of regional differences in the dynamics of reaction of the cerebral hemisphere lobes in response to ischemic-reperfusion injury charachterized by the intensity of apoptosis of neurons and glial cells. The results also point for modifying effect of diabetes mellitus on the indices studied.