Several ethanol selective mixed matrix membranes were prepared from the copolymer of butyl acrylate and styrene and an organophilic nano size clay filler. The clay was incorporated in the polymer during its synthesis from the butyl acrylate and styrene monomer by emulsion polymerization in water. These membranes were characterized and used for the separation of 2.5–15wt% ethanols from water by pervaporation. The mixed matrix copolymer membrane containing 2% (wt% of total polymer) clay was observed to yield the best result, i.e., a flux of 0.34kg/m2h and an ethanol selectivity of 26.4 at 30°C for 5wt% ethanol in water. The permeability, intrinsic membrane selectivity and concentration average diffusion coefficients of the solvents were also determined.