The behaviour and roles of the microtubule network and the microfilaments following fertilization in the mouse oocyte are described. The microtubule network is organized by multiple microtubule organizing centres (MTOCs) and these play a major role in establishing spindle structure and pronuclear movement following fertilization; in contrast to sea urchin and frog eggs, the sperm centriole plays little part in organization of the post‐fertilization spindle. The microfilaments are required for spindle rotation, polar body formation, certain changes in the egg cortex, (...) and also for pronuclear movement. Influences of the chromosomes on microtubule and microfilament organisation are also discussed. (shrink)