In this review, we summarize the important recent findings relating to arsenate respi‐ration by bacteria. A brief discussion of freshwater arsenic cycling is provided, with attention placed on the microbial contributions to this cycle. The basic evidence for microbial growth on arsenate is presented for studies with both consortia and isolates, followed by a summary of the physiology and phytogeny of four arsenate‐respiring bac‐teria:Chrysiogenes arsenatisstrain BAL‐1T, Desulfotomaculum auripigmentumstrain OREX‐4, Sulfurospirillum arsenophilusstrain MIT‐13, andS. barnesiistrain SES‐3. Drawing on biochemical studies of the arsenate reductasefromS. barnesiistrain SES‐3, a preliminary model for growth on arsenate is proposed. We conclude with a discussion of the importance of microbial arsenate reduction in the environment.