A simulation model for heterogeneous distillation proposed by Saito dal. (1998)is modified by taking account of mass transfer resistance in the aqueous and organic liquid phases. In the present model, the heat and mass transfer rates between the vapor and each liquid are calculated separately, The simulation results are compared with the experimental data obtained previously by a wetted-wall column for an ethanol-benzene-water system. The predicted reflux flow rate is improved compared with the previous simulation model where mass transfer resistance in the liquid phase is ignored, and the prediction accuracy is less than 10% of the observed values.