AbstractChlorophenols are a class of chemicals commonly used in preservatives, disinfectants, algaecides, herbicides and pesticides. However, there is a growing evidence that these compounds are a threat to human health. This is alarming as many chlorophenols are common pollutants found in the global environment at potentially biohazardous levels. Despite chlorophenols being abundant, widely used and poisonous, we know relatively little about their mechanism of toxicity in eukaryotes. Thus, we performed genome‐wide growth screens usingSaccharomyces cerevisiaeto understand the molecular basis of chlorophenol toxicity. Of ∼4850 single gene knockout strains tested, 393 mutants showed growth sensitivity to treatment with 4‐chlorophenol (4‐CP), 2,4‐dichlorophenol (2,4‐DCP) or pentachlorophenol (PCP). Only eight mutants showed growth hypersensitivity to all the three treatments and harboured deletions in genes important for aromatic amino acid biosynthesis (ARO1, ARO7) or mitochondrial protein synthesis and respiration (ATP5, ISA1, RML2, GET2, SLS1, MRPL38). Copyright © 2010 John Wiley & Sons, Ltd.