We demonstrate applicability of the open-circuit potential (OCP) method for kinetic analysis of the oxidative chemical polymerization of aniline both in clear solution and in dispersions of multiwalled carbon nanotubes (MWCNT). The characteristic points and the shape of the OCP profile are used to estimate the kinetic parameters of the main stages of the known two-step polymerization mechanism of aniline. We have found that the reciprocal values of the duration of the main polymerization stages namely the induction period, pernigraniline (PN) accumulation and reduction of PN with residual aniline are the linear functions of the weight fraction of MWCNT. To compare the kinetic data of the proposed OCP and known approaches the last two stages have been considered as a single heterogeneous stage of emeraldine (EM) formation. The kEM rate constant calculated by the OCP profiles for this EM stage in the solution and dispersion media is in a very good agreement with the known k(2) values.