Latex membranes have shown potential to be a new type of pervaporation separation membrane. Three types of latex membranes were prepared in our laboratory by direct casting of polymer latexes. These latex membranes were selective toward water during pervaporation with ethanol-water mixtures. The free-volume approach was employed to characterize the pervaporation of these latex membranes. It is shown by this experiment that the Yeom-Huang model, which is based on the free-volume theory and the thermodynamics, can be used to model the pervaporation process of the latex membranes which give reasonable predictions on the permeability.