Polyvinyl alcohol/poly-2-acrylamide-2-methyl propane sulfonic acid/polyethylene glycol blend membranes were cross-linked by glutaraldehyde in acetone to give water-insoluble film with an excellent ionic conductivity. The water-swelling ratio (WSR) of the membranes was decreased by treating with glutaraldehyde accompanied by increasing proton conductivity. Excellent proton conductivities (0.02-0.083 S cm(-1)) were obtained for the resulted cross-linked blend membranes. Methanol permeability of the cross-linked film was significantly low, around one-fifth as low as that of Nation. (c) 2005 Elsevier B.V. All rights reserved.