Cellulose nitrate(NC)-Poly(methyl acrylate) (PMA) blended membranes were obtained transparently by casting their mixtures in acetone. The permselectivity of the membranes for mixtures of H2O and some alcohols was examined by pervaporation. Glass transition temperature, density and molar refractive index of the blends at various compositions showed almost linear dependences on the composition, which suggested a good compatibility of these polymers. The interaction parameters between NC and PMA obtained by sorption experiments of H20 and the alcohols showed negative values which indicated their good compatibility. The sorbed amounts and permeation rates of H2O and the alcohols and the apparent diffusion coefficient of H2O showed minimum values at a composition of NC : PMA=1 : 1 in volume ratio, as suggested by the interaction parameters between NC and PMA. Maximum separation factors for H20 and the alcohols were obtained for the 1:1 composition membrane.