To study the role of YDL100c during the growth of Saccharomyces cerevisiae in the presence of oxidant, the wild type strain (WT) and YDL100c disrupted strain (KO) were grown at 30oC for 6 hr after adding 0.25 mM of tert-butyl hydroperoxide (t-BOOH). The cells of both strains were assayed for the expression of anti-oxidant system, trehalose accumulation, intracellular molecular oxidation level, membrane lipid peroxidation, and glutathione (GSH) content. The results show that growth of KO is slower than that of WT and the cause of growth delay is the cell death. The data also show that the molecular oxidation level is lower but the lipid peroxidation of membrane is higher in KO compared with WT in the presence of t-BOOH, indicating that ROS do cause the damage on membrane. Further, analysis of the expression of cellular defense-related genes show that expressions of GSH1, CTT1, TPS1, TSL1, and NTH1 in KO are lower than in WT, but expressions of SOD1, TRR1 and TRX1 have no difference, demonstrating that the deletion of YDL100c in S. cerevisiae affects the general and specific stress response when grown in the presence of t-BOOH. In general, the decrease in CTT1 expression is not consistent with the catalase activity assay, however, decreased expressions of GSH1 and genes involved in trehalose metabolism are consistent with the decreased GSH content and increased trehalose accumulation in KO compared with WT. Therefore, the cause of KO cell death in the presence of t-BOOH is most likely related to the decrease in cellular GSH level and trehalose accumulation.