The morphological changes in actin cytoskeleton, taking place during apoptosis in cells of the human leukemic HL-60 cell line, were described. It is concluded that the actin cytoskeleton is a dynamic structure actively involved in the executive phase of the process of apoptosis. It is suggested that the rearrangement of the microfilament network and its subsequent degradation are necessary for the main morphological changes of apoptotic cells, i.e., plasma membrane blebbing and apoptotic bodies formation.