Oxidative stress is thought to promote aging by damaging various cellular components. We investigated the phenotypic effects of mutation in the sdhC gene encoding succinate dehydrogenase C in Drosophila by using transgenic flies expressing a dominant-negative form, SdhC(I71E). Expression of SdhC(I71E) significantly reduced the mean lifespan by 22% compared to that of control flies. The amount of protein carbonyl was significantly increased, suggesting that a high level of oxidative stress was induced in these flies. The transgenic flies should serve as a model for studying the biological processes associated with increased levels of oxidative stress and mitochondrial dysfunction in Drosophila.