Repeated stimulation of division soon after the primary one (2--3 days later) induces a shorteining of the prereplicative phase of the mitotic cylce of hepatocytes to 9--10 hours in the regenerating rat liver. The cells dividing repeatedly after one stimulation were found to pass through the G1-phase of the second mitotic cycle during the same period. It may be suggested that the cells with the minimal duration of the prereplicative phase failed to pass through the transformation period. With increase of the time interval between the successive stimulation of divisions (to 4--5 days) increases the resting time state for most hepatocytes, and they lose the capacity to pass through the reduced prereplicative phases.