The accumulation of molecular damage from attack by reactive oxygen species is one cause of aging. Therefore, some mutant organisms showing increased resistance to reactive oxygen species should live longer. We show that selection for Caenorhabditis elegans mutants that are resistant to juglone, a reactive oxygen species-generating compound, leads to the identification of long-lived mutants. Indeed, four of six resistant mutants isolated were also long-lived. This study illustrates once more the strong relationship between oxidative stress and the aging processes.