To meet with the requirement of proton exchange membrane in direct methanol fuel cells (DMFCs), sulfonated poly(aryle ether ketone sulfone)/ polypyrrole (SPAEKS/Ppy) composite membranes with different contents of Ppy were prepared by chemically in situ polymerization. FT-IR spectra suggested that the sulfonic groups on SPAEKS copolymers interacted with N groups of Ppy. SEM pictures showed that the Ppy particles were uniformly distributed throughout the SPAEKS membranes matrix. The composite membranes showed good thermal stability, low water uptake, and high proton conductive capability. The methanol diffusion coefficient (1.18 x 10(-7) cm(2)/s) of the composite membrane with 15% Ppy was much lower than that of pure SPAEKS membrane (8.52 x 10(-7) cm(2)/s). The composite membranes showed very good potential usage in direct methanol fuel cells (DMFCs). (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 914-920, 2011