In this paper grafting of mesoporous γ-alumina membranes with monovinyl terminated polydimethyl- siloxane (PDMS), using 3-mercaptopropyltriethoxysilane (MPTES) as a linking agent, is described. The grafting performance of the organic moieties on γ-alumina powders was studied by FTIR. Contact angle measurements and solvent permeability tests were used to characterize the membrane properties. The results indicated that grafting reactions were successfully carried out. The toluene permeability of the membrane was reduced from 5.3 to 2.1 L/m2 h bar after grafting with the polymer. No degradation of the membrane material was observed after chemical stability tests in toluene for 6 days at room temperature and at elevated temperatures (up to 90 1C).