The poster aims to provide an insight of the work performed within a bilateral project of Greek-Czech cooperation focused on CO2 geological storage prospects of both countries. An overview of major CO2 point sources as well as the estimated storage potential of saline aquifers and hydrocarbon reservoirs suitable for carbon dioxide underground storage in proximity to concentrated emissions in the Czech Republic and to the Tertiary sedimentary rocks of Greece will be presented. The energy market of both countries is dominated by the use of fossil fuels. Lignite-fired stations accounted for 60% of total electricity production in Greece and for 50% in the Czech Republic in 2003. Selected potential storage sites in both countries will be mapped providing also the geological characteristics of the potential sedimentary basins. For Greece, the theoretical storage capacity of the Prinos depleted oil field in the northeast of the country was estimated at 17 Mt CO2. A greater storage potential of 2.2 Gt CO2 has been calculated for deep saline aquifers. The aquifer in the molasses sediments of the Mesohellenic Trough and the sandstone aquifer in Thessaloniki Basin are localized in a favourable distance from Ptolemais-Amynteo lignite-fired power stations and refineries fertilizers and cement plants in Thessaloniki respectively. Finally, the potential to store CO2 as an enhanced CBM option in Ptolemais-Amynteo area coal basins at depths of 500 – 1000m will be presented. In the same basin two aquifers have been identified, a carstic and an alluvial, as potential candidates for CO2 storage. The carstic aquifer is a carbonic sequence of limestones and marbles at a depth of 800m with a thickness which at places exceeds 1000m. However an evaluation of geological, geophysical, geochemical and reservoir engineering data is further required in order to estimate the storage potential of these geological structures. For the Czech Republic, results of the ongoing research focused on deep saline aquifers situated in the Central-Bohemian Permian/Carboniferous basins will be pointed out as the most promising CO2 storage option in the western part of the country where major CO2 emission sources are situated.