The annual glacier mass balance of Mullwitzkees in Hohe Tauern is measured since 1.10.2006 with the direct glaciological method in the fixed date system (1.10. to 30. 09. of the following year). The accumulation of snow is measured by determination of the water equivalent in 6 snow pits, the ice ablation is measured with 15 stakes drilled into the ice. Results are the annual net mass balance in kg, the total accumulation and ablation, the glacier area and the portions of the area which are subject to ablation and accumulation, the elevation of the equilibrium line and the specific mass balance in kg/m² (= mm w.e.). The accumulation during the winter is determined by the 1 May. The project is funded by the Hydrographischer Dienst der Abteilung Wasserwirtschaft des Amtes der Tiroler Landesregierung and National Park Hohe Tauern. The measurements are carried out by the Institute of Interdisciplinary Mountain Research of the Austrian Academy of Sciences.