Mammalian cells of different origin (11 strains) were cultivated at the temperature of 25--41 degrees to measure the temperature limits of mitosis. Different strains of the cells reacted to the increase or decrease in the cultivation temperature in a dissimilar way. The difference between the upper temperature limit and the optimum one was not over 5 degrees. Cell division did not end with the temperature fall by over 10 degrees. Various cell strains responded to the temperature decrease in a different way. Most cellular population had three cell types. The majority of the cells were capable of dividing at the threshold temperature; some cells could enter mitosis without completing it and stop at the metaphase. The temperature limits of mitosis were not related to the species and tissue origin of the cells.