This article reviews how epidemiological measures can be used in health planning. Theoretical considerations are discussed together with empirical data from Sweden. Formulation of targets, priority settings, resource allocation and monitoring systems are some ways in which epidemiological data can improve health planning. One important lesson for planning is that problems related to health, inequalities in health, and access to care, must be made visible to politicians, health personnel and the public. Further, there is a need to complement a national health policy with a decentralized planning system that takes local conditions and needs into consideration.