This research investigated the influence of three layouts of operating rooms on the indoor environment control, on thermal comfort and on energy consumption. It was used the EnergyPlus software. The parameters of the environment were described in accordance with standards. The three layouts had controlled the temperature and relative humidity. The patient presented extreme discomfort. The anesthesiologist presented much discomfort and in some cases discomfort. Other people remained in comfort or a little discomfort. The layout combining two hallways and an operation room indicated the best thermal sensation for the people, and the lowest energy consumption.