In the present study, magnetic iron-zirconium co-oxide microspheres were successfully synthesized by the emulsion and coprecipitation method in a single step. To obtain the ultimate material that possesses high zirconia content and suitable magnetic response, the ratios of the reactants were investigated systematically. The corresponding microspheres were characterized by scanning electron microscopy (SEM), X-ray fluorescence (XRF), powder X-ray diffraction, (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption measurements. The magnetic property of the particles was studied by a magnetic balance. The results demonstrated that the optimum ratio of zirconium precursor (zirconyl chloride) to iron precursor (ferric trichloride) was 3.0:5.0 g, in which microspheres with diameter of 2-5 mu m, high surface area up to 62m(2)/g, and suitable magnetic property were obtained. The magnetic iron-zirconium co-oxide microspheres are promising in various applications, including catalysis, bioseparation, drug carrier, etc.