Background: Little is known about how bacteria sense or respond to reactive chlorine species, such as bleach. Results: NemR is a redox-regulated transcription factor which senses bleach. Conclusion: NemR controls expression of genes encoding electrophile detoxification enzymes, which increase bleach resistance. Significance: We demonstrate a bleach-sensing bacterial response system and a new mechanism contributing to bacterial bleach survival. Copyright © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.