The simulation technique has been widely used as a tool in the decision making process. The present work proposes the use of this tool to evaluate the current performance of the International Airport of Rio de Janeiro Antonio Carlos Jobim (Galeão) concerning the aircraft movements of arrivals and departures, estimating, among other measures, the saturation point of the airport, and consequently evaluating the current level of service provided, aiming, if necessary, to propouse modifications in its infrastructure. The software used in the simulation is presented and explained in details in order to describe the sequence of procedures adopted to obtain the results of this study. For the estimation of the necessary parameters in the simulation, recent data, in the form of time series, of the aircraft movement procedures in the Galeão Airport, will be used as well as local infrastructure data locally available.