Authors have studied 484 patients, aged from 35 to 55 years (mean - 41.0±1.4 years), in the early stages of cerebrovascular insufficiency. Computed morphodensitometry of erythrocytes, the study of their deformation and aggregation capacity have been used. It have studied the subpopulation content of erythrocytes and determined their morphometric parameters. The morphodensitometric changes in erythrocytes were correlated with disturbances of their functions (aggregation properties, deformation, gas transfer ability) that had the most impact on the hemodynamics of the microcirculation stream. Clinical and laboratory studies revealed that the morphofunctional changes in erythrocytes appeared earlier and played a key pathogenetic role in the formation and progression of cerebral ischemic hypoxia.