['To observe the effect of prolonged feeding of dietary nucleotides (NTs), and to clarify the effect of NTs on life extension of Sprague-Dawley rats.', 'There were 50 Sprague-Dawley rats in each group (male:female ratio=1:1), which were fed diets supplemented with NTs at concentrations of 0%, 0.01%, 0.04%, 0.16% and 0.64% (wt/wt) from the age of 4 weeks until natural death. We investigated the moribundity and mortality, survival time, spontaneous tumor incidence, and serum oxidative status.', 'NTs have signiﬁcantly inﬂuence body weight of first 3 month old and food consumption of male rats throughout the life span; it did dose-dependently inhibit the age-related decrease in the activities of antioxidant enzymes and the age-related increase in the levels of lipid peroxidation product in both sexes. NTs notably increased the mean life span, and the maximal life span. Compared to the control group, the incidence of death from tumors was decreased in NTs groups of both sexes.'] Do dietary nucleotides extend the life span in Sprague-Dawley rats?