The compilation of harmonized geological and geothermal models and maps at the W-ern part of the Pannonian basin, covering parts of Hungary, Slovenia, Austria and Slovakia made it possible to delineate potential geothermal reservoirs at regional scales, which are often cut-cross by country borders. Altogether 18 types of potential geothermal reservoirs were identified as a combination of their lithology (Upper Pannonian porous sediments, Miocene sedimentary rocks with intergranular and/or double-porosity, basement fractured crystalline Palaeozoic rocks, and basement fractured [partly karstifled] Mesozoic carbonate rocks); temperatures (50, 100 and 150 degrees C); and hydrogeochemical character of the stored fluids. All identified reservoirs were delineated and shown on maps and the various categories were briefly characterized in terms of their porosity type, hydraulic connections, hydrogeochemistry, as well as utilization potentials. The maps outline prosperous regions for future project developments for various utilization purposes (balneology, direct use, combined heat and power), but most importantly create the basis for a harmonized cross-border management of deep geothermal resources shared by neighbouring countries in the Pannonian basin.