The paper systematizes the data of the literature on ultrastructural changes in the central nervous system (CNS) of experimental animals infected with arboviruses of the Togaviridae family. The main site of virus reproduction in the CNS was found to be nerve cells in which the ultrastructural lesions typical for this group of viruses developed. The main features of these lesions consist in degeneration of rough membranes, ribosomes, and polysomes of the cell, hyperplasia and hypertrophy of smooth membranes, formation of various vacuoles and vesicles in the cell hyaloplasm. Mature virions accumulate in cisterns and cavities of the endoplasmic reticulum, lamellar complex, in vacuoles and vesicles. Each of arboviruses produces in the cells not strictly specific but typical ultrastructural lesions. In the CNS the viruses spread hematogenically, in intercellular and perivascular spaces and dendrites of the nerve cells.