Abstract : Medical advances and increasing life expectancy have indirectly contributed to the development of chronic complex diseases. Chronic diseases, which last for a lifetime, are responsible, at least in part, for the increase in health care expenditures which poses new challenges to healthcare systems. Under increasing economic pressure, it has become increasingly important to efficiently allocate scarce healthcare resources. By comparing costs and effects of health interventions, health economic evaluation is a powerful tool to help decision makers to make rational decisions. This a rticle introduces the methods for the economic evaluation of health care programs and discusses the challenges of using economic evaluation in médical decision making.