Polypyrrole microstructures with morphology like bowls, cups and bottles have been generated electrochemically by direct oxidation of pyrrole in an aqueous solution of camphorsulfonic acid. The well-ordered microstructures stand upright on the working electrode surface in a high density. Their morphological features can be easily controlled by changing the electrochemical polymerization conditions and the results have good reproducibility. The growth process of microstructures was studied by scanning electron microscopy and optical microscopy. Based on the experimental observations, a self-assembled gas bubble template mechanism was postulated. (C) 2003 Elsevier B.V. All rights reserved.