Microbes present special opportunities for proteomic analysis that are not yet available for other types of organisms, due mainly to the relative abundance of information on their genomes, their low levels of functional redundancy and their experimental tractability. They are also being used to develop and validate powerful new experimental approaches that surmount some important current limitations in this field. The review surveys the different proteomic procedures that are available and considers the advantages and disadvantages of different experimental strategies. The ways in which microbiologists - and others - can exploit proteomic data are also discussed.