INTRODUCTION Soil moisture monitoring and the characterization of the spatial and temporal variability of this hydrologic parameter at scales from small catchments to large river basins continues to receive much attention, reflecting its critical role in subsurface -- land surface -- atmosphere interactions and its importance to drought analysis, crop yield forecasting, irrigation planning, flood protection, and forest fire prevention [1, 2, 3, 4]. We will describe the objectives and methodologies of an Envisat project that will aim to produce maps of seasonal soil moisture patterns at the regional scale based on ASAR imagery. The work will be carried out for two river basins that have significantly different climatic, geologic, and land use characteristics: the Flumendosa basin in Sardinia (Italy) and the larger Meuse basin that drains a good part of Belgium and the Netherlands as well as portions of France, Germany, and Luxembourg. High resolution ASAR data will be acquired over se