Chitosan-ferrocyanide sorbents (CFS) based on ferrocyanides Ni-K, Cu-K and Zn-K for concentrating Cs-137 from the seawater have been obtained. Sorbent CFS Zn-K can be used in sorption-regeneration cycle using 5 M solution of NH4NO3 as the eluent. In dynamic condition, the sorption efficiency of Cs-137 and the elution for the CFS Zn-K exceeds 95%. The two-staged scheme of Cs-137 concentrating from seawater is suggested. First stage is the removal of radionuclide from seawater by the CFS Zn-K sorbent, and the second stage is the sorption of Cs-137 from eluate by the CFS Ni-K sorbent.