The sorption and pervaporation properties of an uncrosslinked latex membrane and its corresponding solvent cast membrane were investigated. Both membranes exhibited preferential water sorption and preferential water diffusion. There were similarities in the sorption and pervaporation properties of these two types of membranes, but significant differences were observed in permeation selectivity. The solvent cast membrane had a higher sorption selectivity due to its higher degree of crystallinity, while the latex membrane had a higher pervaporation separation factor, due to the highly selective diffusion through the hydrophilic boundary regions. This phenomena was explained according to the carrier transport mechanism. The permeability and selectivity of both membranes were functions of the feed composition. The dependence of permeability of these membranes on feed temperature was correlated by the Arrhenius relationship.