The surface morphology and structure of electrochemically deposited polypyrrole films have been investigated by electron probe microanalysis, crossed polar optical microscopy, and X-ray diffraction (XRD). The films have been shown to possess only low levels of crystalline order despite a mature morphology indicative of highly ordered spherulitic structure. We suggest that the morphological features observed are the result of the production of gaseous oxygen at the working electrode surface during electrochemical deposition. This has strong implications for the electrical characteristics and gas-sensing function of the films.