The microtubular element of the plant cytoskeleton undergoes dramatic architectural changes in the course of the cell cycle, specifically at the entry into and exit from mitosis. These changes underlie the acquisition of specialized properties and functions involved, for example, in the equal segregation of chromosomes and the correct positioning and formation of the new cell wall. Here we review some of the molecular mechanisms by which the dynamics and the organization of microtubules are regulated and suggest how these mechanisms may be under the control of cell cycle events.