The experimental data of Walcek et al. (1981) for SO2 absorption by falling water drops of 600 mum dia. at 13-15-degrees-C and 1-50 vol% SO2 in air can be well predicted by a model which ignores the effect of internal circulation and considers the diffusion of both SO2 . H2O and HSO3- and the accompanying equilibrium dissociation reaction Of SO2 . H2O Within the drop. The data can also be described by the analytical solution obtained by simplifying the rigorous model with the assumption that the gas phase mass transfer resistance is negligible and that the diffusivities of sulfur species are equal.