Economic evaluations figure largely in health care. Economic evaluation aims at offering structured information about the balance between costs and effects of a intervention in comparison to another intervention. Four basic types of economic evaluation studies exist: cost-minimization analysis, cost-effectiveness analysis, cost-utility analysis, and cost-benefit analysis. In deciding which types of evaluation should be used in the analysis, the aim of the analysis is determinative. This article illustrates the theory of economic evaluation and concentrates on its use within cardiology. Finally, this article describes the project "Appropriate Medical Care," a project developed by the Royal Dutch Medical Association. In this project results from cost-effectiveness analysis will be taken into consideration in forming guidelines for the treatment of coronary artery diseases.