The location, geological structure and characteristics of the Kamionki Anticline is presented in terms of possibility of underground CO2 storage. It is situated in the Płock Trough, in the SW part of the Płońsk Block, and represents a synsedimentary graben originated in the Early and Middle Jurassic. It has been explored by a semi-detailed reflection seismic survey and three deep boreholes (Kamionki 1, Kamionki 2 and Kamionki IG-3). Assuming that the anticline is conventionally outlined by a contour line of the top of the Lower Jurassic, its length is about 15 km, width is about 5 km and the area reaches approximately 75 km2. Geological, seismic and reservoir property data allow concluding that this structure is suitable for underground carbon dioxide storage. The primary reservoir level for underground CO2 storage is represented by Barremianmiddle Albian deposits of the Mogilno Formation with an average thickness of 170 metres, containing on the average 85% of sandstones, and showing porosity of about 20% and permeability above 100 mD up to 2000 mD. The sealing series is composed of Upper Cretaceous marls, limestones and chalk reaching the thickness of about 1000 metres. The secondary reservoir level is represented by upper Toarcian deposits of the Borucice Formation.