Classically, aging has been defined as a general degeneration process that leads to the loss of corporal function. The loss of function caused by degeneration limits the maximum lifespan of all organisms and is linked to disease and cancer. Nevertheless, the molecular mechanisms behind aging and their connection to cancer are not well understood. NAD-dependent protein deacetylase enzymes, sirtuins, are emerging as a novel molecular link between aging and cancer due to their specific role in cell cycle regulation, antistress response and cell survival. This article reviews the contribution of sirtuins and environmental factors to ontogenic development, senescence and cancer.