Cytokinesis is a process through which the cytoplasm of the mother cell gets divided and distributed equally in the daughter cells. In animal cells, this process begins in anaphase and continues till the end of telophase.
Mitosis basically comprises 4 stages :
(1) Prophase
(2) Metaphase
(3) Anaphase
(4) Telophase
Till prophase and metaphase most of the events that occur are concerned with initial changes in the nucleus like condensation of chromatin and lining up of chromosomes in the equatorial plate. But, as the mitosis proceeds further the events related to separation of chromatids and their movement towards opposite poles also gets completed till anaphase. So, the only major event left after that is cytokinesis which begins in the anaphase itself and gets completed by the end of telophase.