Hydrometeorological investigations are being carried out by the Meteorological Service of the German Democratic Republic in four experimental basins with different altitudes, surface areas and physico-geographical features. This research work predominantly aims at the exploration of the water balance of the respective area, including the possibilities of extending the results by way of extrapolation to larger areas; the setting up, verification and improvement of methods designed for determining the individual components of the water balance, especially the precipitation and evapotranspiration in the respective areas; as well as for obtaining increased knowledge with regard to the heat and water balance of the snow cover. In the following, some of the hitherto achieved results of this complex research activity will be presented.