Hydrolizedthree-dimensional copolymer of maleic anhydride, styrene and 1,4-di(4-izopropenylphenoxy)butane has been studied as a synthetic sorbent for extraction of 235U and 238U isotopes out of water solutions. It has also been established that in the solutions at concentration of uranyl-ion 212.0 mg/l and 636.0 mg/l a sorption degree of sorbent on UО22+ ion makes up 96.5% and 80.6%, volumetric capacity 204.4 mg/g and 512.3 mg/g accordingly (pH=7, 24 hour sorbtion). Also established, that it is possible to regenerate through desorption of the sorbent containing 230.0 mg/g uranyl-ion with the help of ~0.1 M hydrochloric, nitric or sulfuric acid.