p53 regulates the cell cycle and deoxyribonucleic acid (DNA) repair pathways as part of its unequivocally important function to maintain genomic stability. Intriguingly, recent studies show that p53 can also transactivate genes involved in coordinating the two major pathways of energy generation to promote aerobic metabolism, but how this serves to maintain genomic stability is less clear. In an attempt to understand the biology, this review presents human epidemiologic data on the inverse relationship between aerobic capacity and cancer incidence that appears to be mirrored by the impact of p53 on aerobic capacity in mouse models. The review summarizes mechanisms by which p53 regulates mitochondrial respiration and proposes how this might contribute to maintaining genomic stability. Although disparate in nature, the data taken together suggest that the promotion of aerobic metabolism by p53 serves as an important tumor suppressor activity and may provide insights for cancer prevention strategies in the future.