Acrylonitrile-Butadiene-Styrene (ABS)/iron nanocomposites have been prepared by cryomilling (high-energy ball milling under cryogenic temperature), and a microstructure of iron network in ABS matrix was obtained. The blending scale and homogenization of ABS/iron nanocomposites are observed by Atomic Force Microscope (AFM). The morphology and structure of cryomilled composite powders are characterized by means of Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and X-ray Diffraction (XRD). The results indicate that upon cryomilling for 20 h, ABS and Fe are intimately blended with the single composite particle size less than 100 nm, the Fe phase domains less than 50 run, and Fe grain size reduced to 20 run. Both the fast rate of homogenization and size reduction are mainly attributed to the introduction of cryogenic temperature and comilling. The evidences suggest that cryomilling is a capable and promising technique for the production of polymer/metal nanocomposites. (c) 2005 Wiley Periodicals, Inc.