Bacterial biofilms are generally described as surface-associated bacterial communities comprising exopolysaccharide-surrounded microcolonies. Interspersed between these microcolonies are water-filled channels that may serve as primitive circulatory systems. Over the past few years, much progress has been made in our understanding of the development of bacterial biofilms. This progress is largely due to the recent focus on analyzing biofilms using genetic and molecular biological approaches. Specifically, researchers have begun to identify the genetic components required for the formation of single-species bacterial biofilms. These findings are leading us to an understanding of the steps involved in initiating biofilm formation and the cellular components required to accomplish these steps.