The film mass transfer coefficient k(w) was measured on the surface of a cylindrical electrode immersed vertically in three-phase systems with fine suspended particles with an average diameter ranging from 0.10 to 1.1 mm, A 50 to 75% enhancement in the values of k(w) in the three-phase systems suspended with fine particles was observed in comparison with those in the beds with coarser particles otherwise operated under similar hydrodynamic conditions. This enhancement was due to erosion of liquid film caused by penetration of particles into the mass transfer film, The values of the mass transfer coefficient were correlated well by a unified dimensionless equation in terms of the energy dissipation rate per unit mass of liquid to cover the liquid-solid and gas-liquid-solid fluidized systems.