Conductive polymer particles, polyaniline (PANI)-coated poly(methyl methacrylate-butyl acrylate-acrylic acid) [P(MMA-BA-AA)] nanoparticles, were prepared. The P(MMA-BA-AA)/PANI core-shell complex particles were synthesized with a two-step miniemulsion polymerization method with P(MMA-BA-AA) as the core and PANI as the shell. The first step was to prepare the P(MMA-BA-AA) latex particles as the core via miniemulsion polymerization and then to prepare the P(MMA-BAAA)/PANI core-shell particles. The aniline monomer was added to the mixture of water and core nanoparticles. The aniline monomer could be attracted near the outer surface of the core particles. The polymerization of aniline was started under the action of ammonium persulfate (APS). The final product was the desired core-shell nanoparticles. The morphology of the P(MMA-BA-AA) and P(MMA-BAAA)/PANI particles was characterized with transmission electron microscopy. The core-shell structure of the P(MMA-BA-AA)/PANI composites was further determined by Fourier transform spectroscopy and ultraviolet-visible measurements. The conductive flakes made from the core-shell latexes were prepared, and the electrical conductivities of the flakes were studied. The highest conductivity of the P(MMA-BA-AA)/PANI pellets was 2.05 S/cm. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1401-1406, 2012