Considerable amount of work has been done on the theoretical prediction of the flow field in the slag and pool of the ESR system. I'2'3 Also, experiments have been performed on cold models. 4 From the qualitative visual observation of the slag surface in the ESR system it is known that the stirring velocities are in the order of a few centimeters per second. But, apparently, no systematic measurements of the flow pattern in the real ESR have been carried out. In the present work measurements performed at the surface of the slag are reported. The fluid flow in the ESR furnace is caused mainly by two effects. 2 First, there is natural convection. The hot slag below the electrode tends to move upward, whereas the cooler slag close to the mold tends to sink downward. A recirculation motion will develop which is directed toward the mold at the free surface of the slag, Second, forced convection is caused by the electromagnetic force F = [j x B]. Since the current density j is larger in the electrode than in the ingot, there results a curl of the force vector causing a circulatory movement which is directed toward the electrode at the free surface of the slag. Hence, this motion is in opposite direction to the natural convection. Under practical conditions there may also be a tangential flow component in addition to the radial and vertical components. The cause is not well known. It may be due to nonsymmetry because the electrode is not centered exactly. Another electromagnetic nonsymmetry may be caused by the exterior cables. Experimental Technique. The experiments were carried out with a laboratory unit using a movable mold of 240 mm internal diameter and electrodes of 100 mm diameter. The small fill ratio was applied in order to obtain the large free slag surface suitable for the velocity measurements. The steel grades used were C 35, St 37, and St 52. The slag had