A novel antibacterial material was developed by surface modification of electrospun polyurethane (PU) fibrous membranes, using a process which involved plasma pretreatment, UV-induced graft copolymerization of 4-vinylpyridine (4VP), and quaternization of the grafted pyridine groups with hexylbromide. The success of modification with poly(4-vinyl-N-hexyl pyridinium bromide) groups on these was ascertained by X-ray photoelectron spectroscopy (XPS). The morphologies and mechanical properties were investigated by scanning electron microscopy (SEM) and tensile test, respectively. The results showed that the morphologies of PU fibrous membranes changed slightly during the modification process and the fiber structures were maintained. The tensile strength of PU fibrous membranes decreased after surface modification, with the smallest decrease (<20%) observed in the membrane with largest diameter. The antibacterial activities of the modified PU fibrous membranes were assessed against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). The modified PU fibrous membranes possessed highly effective antibacterial activities and may have a wide variety of potential applications in high-performance filters, protective textiles, and biomedical devices. (C) 2008 Elsevier B.V. All rights reserved.