Gcn5 is a coactivator protein that contributes to gene activation by acetylating specific lysine residues within the N termini of histone proteins. Gcn5 has been intensively studied in the budding yeast, Saccharomyces cerevisiae, but the features of genes that determine whether they require Gcn5 during activation have not been conclusively clarified. To allow comparison with S. cerevisiae, we have studied the genome-wide role of Gcn5 in the distantly related fission yeast, Schizosaccharomyces pombe. We show that Gcn5 is specifically required for adaptation to KCl- and CaCl(2)-mediated stress in S. pombe. We have characterized the genome-wide gene expression responses to KCl stress and show that Gcn5 is involved in the regulation of a subset of stress response genes. Gcn5 is most clearly associated with KCl-induced genes, but there is no correlation between Gcn5 dependence and the extent of their induction. Instead, Gcn5-dependent KCl-induced genes are specifically enriched in four different DNA motifs. The Gcn5-dependent KCl-induced genes are also associated with biological process gene ontology terms such as carbohydrate metabolism, glycolysis, and nicotinamide metabolism that together constitute a subset of the ontology parameters associated with KCl-induced genes.