It is usually recommended that future costs and health effects are discounted at the same rate, usually 5%. In this paper it is argued that, from a societal perspective, this approach may be inappropriate for health effects. Instead of basing the discount rate for health effects on that for costs, it should be based on the real change in the (societal) valuation of health effects over time. Such valuation may change because of increasing life-expectancy and diminishing marginal utility of additional health effects over time.