Results of the zonal forecast of the prospects for disposing carbon dioxide in the aquifers of the Leningrad sedimentary basin are presented. The highest potential relates to the zone of the Krestetsky aulacogen, where the maximum thickness of the sedimentary cover exceeds 2 km. Within this zone, there are two regional fluidimpermeable horizons: the Lower Cambrian impermeable horizon and the Upper Ediacaran impermeable horizon, occurring at a depth of more than 900 m. The underlying Precambrian sediments contain highly saline waters that are not used for household purposes. The temperature and pressure conditions allow disposing carbon dioxide in water-dissolved and supercritical states. Modeling results show that carbon dioxide can be disposed within the Leningrad basin in the amount of more than 14 mlrd t.