Rates of mass transfer from the liquid phase to small ion exchange resin particles (0.78mm in mean diameter)in fluidized and spouted beds were studied experimentally. Dilute aqueous solution of sodium hydroxide was fed into the beds of strong cation exchange resin and the exit concentration of the solution was determined by conductivity measurement. In spouted beds, the initial conversion and K_L increased with bed height, but decreased with fluid flowrate. The model, applying material balance of the reactant and axisymmetric flow of fluid int eh annulus of a spouted bed, predictions of the initial conversion in spouted beds are satisfactory. In fluidized beds, the obtained mass transfer coefficients were correlated and compared with other works.