Polysiloxane xerogels with immobilized calixarenes and covalently bonded calixarene-crown-6 were obtained by sol-gel method. The presence of functional groups introduced in the structure of xerogels was confirmed by FTIR spectroscopy. The synthesized materials are characterized by the developed specific surface area (120-643 m
/g) and are able to extract cesium ions in acid medium. It was determined that the quantity of functional groups that take part in this process is 40% maximum.