The function of catalases A and T from the budding yeastSaccharomyces cerevisiae(ScCta1andScCtt1) is to decompose hydrogen peroxide (H2O2) to mitigate oxidative stress. Catalase orthologs are widely found in yeast, suggesting that scavenging H(2)O(2)is crucial to avoid the oxidative damage caused by reactive oxygen species (ROS). However, the function of catalase orthologs has not yet been experimentally characterized in vivo. Here, we heterologously expressedDebaryomyces hansenii DhCTA1andDhCTT1genes, encodingScCta1andScCtt1orthologs, respectively, in aS. cerevisiaeacatalasemic strain (cta1 Delta ctt1 Delta). We performed a physiological analysis evaluating growth, catalase activity, and H(2)O(2)tolerance of the strains grown with glucose or ethanol as carbon source, as well as under NaCl stress. We found that both genes complement the catalase function inS. cerevisiae. Particularly, the strain harboringDhCTT1showed improved growth when ethanol was used as carbon source both in the absence or presence of salt stress. This phenotype is attributed to the high catalase activity ofDhCtt1detected at the exponential growth phase, which prevents intracellular ROS accumulation and confers oxidative stress resistance.