Separation of the benzene/cyclohexane mixture is industrially significant. The aim of the study is to disrupt the azeotropic behaviour of the benzene/cyclohexane mixtures by pervaporation using Pebax membranes. To overcome the difficulty of the separation benzene/cyclohexane mixtures by conventional techniques, pervaporation should be used. For this purpose, sorption and pervaporation of benzene/cyclohexane mixtures was studied by using different grades of Pebax (poly(ether-block-amide)) polymer which has soft segments as ether and a hard segment as an amide. It was examined that increasing hardness of the polymeric membrane resulted decreasing pervaporation flux and increasing pervaporation selectivity. Swelling degrees of membranes are decreased front softer to harder grades. Benzene/cyclohexane mixture composition and temperature effects on sorption and pervaporation characteristics are determined at 30, 40, 50 degrees C. Increasing concentration of benzene resulted increasing flux and decreasing selectivity. Fluxes were increased and selectivity decreased with increasing temperature.