Composite polymer membrane has been fabricated on platinum foil using electrochemical deposition of pyrrole and aniline as monomers. The composite has been used as an electrode to analyse ornidazole. The results were comparable with the glassy carbon electrode. The mechanism of biological action of ornidazole is dependent upon the nitro group reduction process. In aprotic medium the reduction of the ornidazole occurs in two steps, the first involving one electron to form the nitro radical and the second step involving three electrons, resulting in the formation of the hydroxylamine derivative.