As seen by EM, interphase hepatocytes with ploidies equal to 2n, 2n .cntdot. 2, 4n, 4n .cntdot. 2 and 8n, the number of centrioles per cell corresponded exactly to the ploidy of the cell. In mononuclear and binuclear cells, the centrioles accumulated in 1 complex in which each pair of centrioles formed a diplosome. In binuclear cells, the diplosome complex was situated at equal distances from each nucleus, making a cell center. The involvement of the supernumerous centrioles in polyploid metaphse cells was detected for the regenerating liver of old mice. Each mitotic pole had at least 4 centrioles. In the pole, a pair of centrioles formed tightly connected diplosomes. The initially tetraploid cell may divide in this manner. How the existence of centrioles can be associated with the polyploidization mechanism was discussed.