A novel strategy was developed to prepare the superparamagnetic polyaniline (PANI) hybrid hollow microspheres via the combination of the interfacial polymerization and Pickering emulsion techniques in oil/water (O/W) emulsion, with the sodium citrate modified Fe3O4 nanoparticles (Fe3O4-CA) as cosurfactant and dopant. The effect of the feeding amount of the sodium citrate modified Fe3O4 nanoparticles (Fe3O4-CA) on the formation of the sodium citrate modified Fe3O4/polyaniline hybrid hollow microspheres (Fe3O4-CA/PANI) was investigated. When the feeding ratio between the sodium citrate modified Fe3O4 nanoparticles (Fe3O4-CA) and aniline reached 1.50, the intact Fe3O4-CA/PANI hybrid hollow microspheres were obtained with high yield and regularity. The diameter of the hybrid hollow microspheres was about 500 nm from the transmission electron microscopy (TEM) analysis. The Fe3O4-CA nanoparticles appeared to increase the stability of the oil droplets during the polymerization and improve the electrical conductivity of the hybrid hollow microspheres. (C) 2011 Elsevier B.V. All rights reserved.