The paper describes the development in airflow simulations in rooms. The research is, as other areas of flow research, influenced by the decreasing cost of computation which seems to indicate an increased use of airflow simulation in the coming years. It is shown that velocity and temperature distribution can be predicted in small rooms of simple geometry as well as in large areas with a complicated geometry, such as theatres, atriums and covered shopping centres. It is also possible to predict variables which are rather difficult to measure as contaminant and humidity concentration, local age and purging flow rate, heat transfer coefficients, etc. Airflow simulation has been used for the prediction of air movement in mixing ventilation, and new research shows that it might also be used for predicting air distribution in displacement ventilation. The paper shows that some development work is necessary to give practical descriptions of air terminal devices. It also shows that it may be necessary to develop a turbulent model which deals with low turbulent flow.