Ethanolamine is a compound that can be readily derived from cell membranes and that some bacteria can use as a source of carbon and/or nitrogen. The complex biology and chemistry of this process has been under investigation since the 1970s, primarily in one or two species. However, recent investigations into ethanolamine utilization have revealed important and intriguing differences in gene content and regulatory mechanisms among the bacteria that harbour this catabolic ability. In addition, many reports have connected this process to bacterial pathogenesis. In this Progress article, I discuss the latest research on the phylogeny and regulation of ethanolamine utilization and its possible roles in bacterial pathogenesis.