Sodium hypochlorite (bleach) is routinely used in hospitals and health care facilities for surface sterilization; however, the mechanism of action by which this disinfectant kills and the extent to which Pseudomonas aeruginosa is resistant to sodium hypochlorite have not been elucidated. Consequently, nosocomial infections from P. aeruginosa result in considerable casualties and economic hardship. We report the genome-wide transcriptome response of P. aeruginosa to sodium hypochlorite-induced oxidative stress via the use of DNA microarrays. In addition to a general oxidative stress response, our data revealed a downregulation of virtually all genes related to oxidative phosphorylation and electron transport and an upregulation of many organic sulfur transport and metabolism genes.