The role of free radicals in aging has been a long-standing theory that has now been extended to include both reactive oxygen and nitrogen species. The original concepts that overwhelming oxidative stress depleted antioxidants and thus damaged intracellular targets is being supplanted by the hypothesis that the reactive species play an essential role in signal transduction. The concept that the cell establishes a redox tone that is altered during the aging process places the oxidative and nitrosative modifications that occur during aging in a new and exciting context. Some highlights of this recent workshop convened by The National Institute on Aging and the Office of Dietary Supplements at the National Institutes of Health are discussed.