Actin and tubulin are the major components of the cytoskeleton that pervades the cytoplasm of all eukaryotic cells. These proteins were traditionally thought not to be present in prokaryotes, but structural and functional homologues of tubulin (FtsZ) and actin (MreB) are now known to be present virtually throughout the eubacteria and in some archae. FtsZ protein is a key player in cell division of bacteria and some eukaryotic organelles. MreB proteins are involved in the regulation of cell shape and the segregation of some bacterial plasmids, and might have a range of other functions. Recent data demonstrate that the bacterial proteins are, like their eukaryotic counterparts, highly dynamic. Here, we review the general properties and functions of actin and tubulin homologues in bacteria, their dynamic behaviour and the implications for understanding cell division and morphogenesis in bacteria.