A silver / nylon 6,6 nanocomposite containing 1 wt % metallic silver has been produced from an aqueous solution of silver nitrate in the presence of ammonia and ethylene glycol by an ultrasound-assisted reduction method. The structure and properties of nylon 6,6 coated with silver have been characterized with X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray, X-ray photoelectron spectroscopy, Raman spectroscopy, and diffused reflection spectroscopy measurements. The nanocrystals of pure silver, 50-100 nm in size, are finely dispersed on the polymer surface without damaging the nylon 6,6 structure. This silver-nylon nanocomposite is stable to many washing cycles and thus can be used as a master batch for the production of nylon yarn by melting and spinning processes. The fabric knitted from this yarn has shown excellent antimicrobial properties. (c) 2007 Wiley Periodicals, Inc.