Although many metal decorated nanotubes and nanowires appear in the literature, well-dispersed metal decorated nanotube polymer composites have rarely been reported because of the excessive density mismatch between the decorated nanotubes and polymer matrix. Here, we report a novel method to prepare well-dispersed, highly functional, metallized nanotube polymer composites (MNPCs) that possess remarkably improved electrical conductivity and mechanical toughness. The MNPCs are prepared by supercritical fluid impregnation of an organometal compound into a premade well-dispersed single wall carbon nanotube-polymer composite film. The infused precursor preferentially migrates towards the nanotubes to undergo spontaneous reduction and form nanometer-scale metal particles leading to an increase in the conductivity of the MNPC films. The environmentally friendly supercritical fluid impregnation process significantly improved the toughness of the composite films, regardless of the presence of metal. Additional functionality can be imparted into the resulting MNPC by infusing other precursors such as magnetic and catalytic metal compounds. (C) 2011 Wiley Periodicals, Inc.* J Polym Sci Part B: Polym Phys, 2012