In this work, polyaniline (PANT)-rhodium composites have been obtained for the first time. Their preparation procedure has involved reduction of Rh3+ ions in RhCl3 aqueous solutions with NaBH4 in the presence of PANT. Using UV-vis spectroscopy, it has been found that the reduction process is fast. X-ray diffraction and Rh3d XPS studies have confirmed that metallic rhodium is incorporated into PANT matrix. SEM and TEM investigations allowed to establish that the sizes of Rh crystallites formed depend on the amount of metal in the composite as well as on the preparation conditions. It has been demonstrated that the composites containing Rh nanoparticles whose size is predominantly below 10 nm can be obtained. IR spectroscopy has proved that PANT chain is protonated in the Rh3+ reduction process. Catalytic properties of PANI-Rh composites have been investigated using isopropyl alcohol conversion as the test reaction. It has been found that the composites containing Rh nanoparticles show high redox activity. Catalytic activity of the composites in which larger, agglomerated metal particles have been present is about three times lower. (C) 2007 Wiley Periodicals, Inc.