A three-dimensional mathematical model of a casting ladle based on fundamental transport equations has been developed. The model may be used for predictions of both a standing ladle and a ladle from which steel is teemed into a tundish. An additional feature of the model is that it can predict concentration profiles of tracer elements which are added to the steel. The predicted concentration profiles during teeming are compared to experimental data from plant trials performed at SSAB and the agreement is found to be good. The model is used as a tool in the development of process control models.