The regeneration potential of differentiated Sertoli cells subjected to thermal treatment was studied by the method of cell transplantation. Cells from mice with artificial cryptorchism (1.5 months after fixation of the testes in the body) and after culturing (10 days, 37°C) were transplanted. Transplantation of Sertoli cells from 2-3-month-old and 2-day-old mice served as controls. The cells were transplanted into the testes of recipient mice, from which sex cells and Sertoli cells were removed by busulfan and cadmium salt treatment. Adult mouse Sertoli cells exposed to thermal treatment exhibited much higher regeneration potential than intact cells. Two months after transplantation, mature Sertoli cells subjected to thermal treatment populated the recipient testicular tubules, formed new tubules, and in some cases supported the development of sex cells similarly as immature cells from newborn mice.