The preferential permeation of benzene over water was achieved with carbon molecular sieve (CMS)-filled polydimethylsiloxane (PDMS) pervaporation membranes. The membranes were characterized by SEM and mechanical strength measurement. The effects of CMS content, benzene concentration in feed solution, operating temperature and feed Reynolds number on the pervaporation properties of the CMS-filled PDMS membranes have been studied. The results showed that the addition of CMS could enhance the mechanical stress of PDMS membranes. With CMS content increasing, permeation flux decreased slightly but separation factor increased to some extent. With the increase of benzene concentration in feed solution and Reynolds number of feed, permeation flux and separation factor both improved significantly. With operating temperature increasing, permeation flux increased but separation factor decreased. (c) 2005 Elsevier B.V. All rights reserved.