Nylon 6 nanofibers containing silver nanoparticles (nylon 6/silver) were successfully prepared by electrospinning. The structure and propertied of the electrospun fibers were Studied with the aid of scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The structural analysis indicated that the fibers electrospun at maximum conditions were straight and that silver nanoparticles were distributed in the fibers. Finally, the antibacterial activities of the nylon 6/silver nanofiber mats were investigated in a broth dilution test against Staphylococcus aureus (Gram-positive) and Klebsiella pneumoniae (Gram-negative) bacteria. It was revealed that nylon 6/silver possessed excellent antibacterial properties and an inhibitory effect on the growth of S. aureus and K. pneumoniae. On the contrary, nylon 6 fibers Without silver nanoparticles did not show, any Such antibacterial activity. Therefore, electrospun nylon 6/silver nanocomposites Could be used in water filters, wound dressings, or antiadhesion membranes. (C) 2009 Wiley Periodicals, Inc. J Appl polym) Sci 112:2320-2326, 2009