The polymerization of aniline (AN) and toluidines [o-toluidine(OTO)/m-toluidine(MTO)] was electrochemically performed on RuO2 in 1.0 M HCl using cyclic voltammetry. The results showed that the rate of polymerization was strongly dependent upon the type of monomer employed. In comparison to the initial rates of AN polymerization, those were higher and lower for MTO and OTO, respectively A kinetic expression for the autoacceleration process in the electrochemical polymerization of these aniline derivatives is expressed as R(p) = k[p] [M] + k’[M] in which k’, k, [M], and [p] are the initiation (nucleation process) rate constant, the rate constant when polymer deposited on the electrode, monomer concentration, and the total amount of polymer, respectively. The ratios of k’/k are 4.5 x 10(-6), 5.4 x 10(-6), and 3.5 x 10(-6), respectively, for AN, OTO, and MTO polymerization. The initial rate of polymerization for these aniline derivatives can be accelerated with slight agitation of the solution. The experimental results of E(1/2) for the first redox process showed that the AN-OTO or AN-MTO comonomer system generated true copolymer rather than the mixture of the corresponding homopolymers.