The use of mathematical models to assess therapeutic alternatives is increasing in the economic evaluation of health technologies and services and these models are becoming an increasingly important aid to decision making in health care.Until now, 2 types of model have been used, depending to some extent on the disease to be studied: decision trees have been used for acute diseases and Markov models in chronic or recurrent diseases. However, both models present major limitations when addressing complex processes or diseases.Consequently, interest in, and the use of, discrete-event simulation is growing.The present article aims to describe the main characteristics of discrete-event simulation, the state of the art in this field, and the advantages of these models with respect to other kinds of models in health economics, especially in the evaluation of health technologies and product assessment.