Polyaniline (PAni) films with similar electroactivity were potentiodynamically grown at selected different scan rates and number of cycles. Palladium particles were incorporated in the electroactive polymer by electroless precipitation. The polymeric matrix morphology and its effect on the distribution and size of Pd particles was analysed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was observed that the dispersion of metal clusters was imparted by the nature of the polymer matrix. The results allowed to state a correlation between the polymer topography and the size and spatial distribution of the catalytic particles. (C) 2004 Elsevier Ltd. All rights reserved.