Polyaniline/Prussian blue micro-composites have been synthesized by a low-temperature hydrothermal process. Prussian blue is obtained using the single iron-source precursor K-3[Fe(CN)(6)] in acidic aqueous solution. The composite was characterized by field-emission scanning electron microscopy (FE-SEM), Fourier transmission infrared spectroscopy (FT-IR), and X-ray diffractometer (XRD). The magnetic behavior of polyaniline/Prussian blue composites and the effect of the concentration of K-3[Fe(CN)(6)] on the morphology of polyaniline/Prussian blue micro-composites have been investigated. (c) 2007 Elsevier B.V. All rights reserved.