Composite membranes based on ethylene propylene diene monomer (EPDM) and polyvinyl chloride (PVC) has been prepared. The vapor permeation studies were conducted with aromatic hydrocarbons and aliphatic alcohols for the membrane characterization. Special attention has been given to the amount of PVC in the membrane, size of penetrant and also type of vulcanization. The permeability was found to decrease with increase in PVC content due to the stiff and rigid nature of PVC. The field emission scanning electron microscopy of the membranes showed a two-phase morphology. Here, the PVC is dispersed in the continuous EPDM phase. It was found that the permeability decreased with increase in the size of the penetrant. Different types of miscible liquid mixtures have been analyzed for finding out the separation efficiency of the membranes. In the case of benzene/propanol mixture, it has been found that when the concentration of benzene increases, the vapor permeation rate increases, indicating high interaction of benzene toward the composites.