Supercritical CO2 extraction is a promising process among existing decontamination methods. Feasibility of supercritical CO2 extraction processing for decontamination of contaminated soils has been studied with non-radioactive cesium as contaminant. Extractant system considered was a mixture of DB18C6 crown ether and HPFOA that gave a synergistic effect when combined. Process parameters influence such as operating pressure (25–29 MPa) and temperature (40–80 °C), initial cesium/extractant/cationic exchanger amounts (molar ratio between 1/12/12 and 1/100/100) and soil moisture (0–6%wt) has been tested. Low temperature (40 °C) and high pressure (29 MPa) allow to optimize process ability for cesium removal. A compromise should be established, for a fixed CO2 flow rate, between amounts of extractants and cationic exchangers. Efficiency of cesium removal seems to be optimized at 3%wt matrix moisture. Extraction from sand is successful with yields up to 95%.