Bacterial surface polysaccharides fulfill a number of important roles in cell-cell interactions, survival in natural environments, and formation of biofilms. Consequently, the mechanisms involved in regulation of extracellular polysaccharides are predicted to have a significant impact on microbial adaptation. Strains of Escherichia coli, Klebsiella spp, and Erwinia spp produce extracellular polysaccharides which share structural features. There are also similarities in the organization of genes required for synthesis of these cell surface polymers and, in some cases, the mechanism of synthesis may be related. Despite the diverse habitats of these bacteria, the systems which regulate expression of their extracellular polysaccharides appear to share components and mechanisms. Understanding these regulatory processes may lead to novel therapeutic approaches for pathogens, or for control of unwanted biofilm formation in industrial settings.