The polymerization of pyrrole (PY) in aqueous or alcohol/water mixed medium in presence of FeCl3 and nanodimensional Al2O3 resulted in the formation of conducting nanocomposites of polypyrrole (PPY)/Al2O3. The incorporation of PPY in the composites was endorsed by FT-IR studies. The extent of PPY loading in the composites decreased with increasing amount of Al2O3 in the initial feed at a fixed PY and FeCl3 amount, respectively. For alcohol-water systems, the extent of PPY loading in the composites decreased with increasing alcohol concentration in the mixture with fixed amount of Al2O3, FeCl3 and PY, respectively. SEM and TEM studies revealed interesting morphological features for the composites prepared under various conditions and confirmed the formation of monodispersed composite particles of diameters in the nanometerrange. TG analyses revealed the enhanced thermal stabilities of the nanocomposites relative to the base polymer. The dc conductivities of the PPY/Al2O3 nanocomposites were in the order of (63 +/- 3 to 33 +/- 5) x 10(-2) S/cm, and the values increasing with decreasing Al2O3 loading in the nanocomposites in aqueous medium but in case of alcohol-water medium, dc conductivities increases with increasing alcohol content in the medium. Some of these nanocomposites could be obtained as stable dispersion during synthesis. (C) 2002 Elsevier Science Ltd. All rights reserved.