Poly (pyrrol-co-o-aminobenzoic acid) has been synthesized electrochemically from an aqueous acid medium. The initial rate of electrocopolymerization reaction on platinum electrode is small and the rate law is: Rate = K-2 [D](1.02)[HCl] (1.44)[M](2.00). The apparent activation energy (E-a) is found to be 90.11 kJ mol(-1). The polymer films obtained have been characterized by cyclic voltammetry, X-ray diffraction, elemental analysis, thermogravimetric analysis, scanning electron microscopy, H-1 NMR, and IR-spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed. The monomer reactivity ratios (r(1) and r(2)) were calculated. (C) 2008 Wiley Periodicals, Inc.