The Gravity Recovery and Climate Experiment (GRACE) satellite mission is now in orbit for more than 7 years. A number of studies regarding periodic signals as well as long-term trends have been carried out. Large scale mass variations have been detected in Greenland and Antarctica (due to ice melt) and North America Fennoscandia (due to glacial rebound). The long time span now also allows detecting smaller secular trends of mass variations as well as long-periodic signals. In our study, we address the permafrost-regime in Siberia, Russia, using the GRACE monthly solutions from the three main analysis centres GFZ, CSR and JPL and further institutions. Two major trends of about 0.5 µGal/yr can be clearly identified one concerning the lower Ob basin, the other centered in the Lena river watershed northeast of Lake Baikal. The observed trends show a different spatial and temporal behavior due to different climate and permafrost conditions. These trends could indicate long-term hydrological changes in the large Siberian watersheds of the Ob, Lena and Yenisei rivers. Earlier terrestrial investigations observe that discharge of Siberian rivers increased during low flow season, possibly caused by reactivation of groundwater as a result of permafrost degradation over the past decades. The GRACE data even indicate some accelerated mass changes in Siberia over the last 5 - 7 years. In this paper, we discuss the corresponding GRACE results and confront them with those from other investigations. Possible explanations for the mass variations in Siberia are given.