Does prosperity lead to greater longevity? If so, what is the strength of the income channel? To address these questions we develop a life cycle model in which households are subject to physiological aging. In modeling aging we draw on recent research in the fields of biology and medicine. The speed of the aging process, and thus the age of death, are endogenously determined by optimal health investments. A calibrated version of the model accounts well for the observed nonlinear cross‐country link between longevity and income, also known as the Preston curve.