The OSR (oxidative-stress-resistance) gene was cloned as the gene which enhances resistance against oxidative stress caused by lipid hydroperoxide in Saccharomyces cerevisiae. The nucleotide sequence of the gene was determined and found to be identical with the zinc-resistance-conferring (ZRCI) gene, which was cloned as the gene enhancing the resistance against zinc and cadmium. A knockout mutant of the OSR gene showed increased sensitivity to lipid hydroperoxide. The intracellular glutathione content in the knockout mutant decreased approx. 40% compared with that of wild-type cells, whereas it increased 3-fold in yeast overexpressing the OSR gene. Therefore the OSR/ZRCI gene product seems to regulate the intracellular glutathione content.