Ferroferric oxide/polypyrrole (Fe3O4/PPy) composites were prepared by an in situ polymerization method. Several analysis techniques including X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis and scanning electron microscopy are applied to analyze the structure and morphology of Fe3O4/PPy. The magnetic Fe3O4/PPy was further used as an adsorbent for removing Eosin Y, methyl orange and brilliant green from aqueous phase. The adsorption kinetics were investigated by pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and the experimental data were well fitted to the pseudo-second order. The equilibrium adsorption data can be described by both the Langmuir and Freundlich isotherm models. The calculated Langmuir maximum adsorption capacities of Eosin Y, methyl orange and brilliant green at 25 degrees C are 212.31, 149.48 and 263.85 mg/g, respectively. Thermodynamic studies indicated that the adsorption process occurred spontaneously, in an endothermic and physisorption nature, and with increased disorder. Furthermore, the convenient magnetic separability of Fe3O4/PPy makes it a good candidate for practical application in the removal of organic dyes from polluted water.