Introduction. The Po basin has been affected in the last sixty years by a strong subsidence due to groundwater pumping from a shallow well-developed multi-aquifer system and oil & gas production from a number of onshore and offshore reservoirs. Once this phenomenon was identified, several monitoring campaigns were carried out by different techniques since the 1897 (Arca and Beretta 1985): precise topographic levelling, GPS, SAR and vertical extensometers. The relatively large amount of observations so far acquired offers the opportunity of monitoring the spatial pattern of land subsidence in the Po Plain, especially for the second half of the 20 th century, when the subsidence dramatically increased. The large diffusion of the space geodetic techniques, as GPS and SAR, in the last twenty years has provided two new tools which have a relatively low cost, and can improve significantly the spatial and temporal monitoring of the subsidence phenomena. So currently, the monitoring