A modified electroless silver-plating process has been devised for the preparation of monodispersed, polystyrene/silver (PS/Ag) composite microspheres with tunable shell thickness. Tailoring was achieved by altering the concentration of the silver precursor in the plating bath. PS/Ag composite microspheres were characterized by field-emission scanning electron microscopy, ultraviolet-visible absorption, X-ray diffraction and thermogravimetric analysis. The results showed that a dense, stable and uniform silver nanoshell was formed on the surface of PS microspheres in the presence of poly(vinylpyrrolidone) and glucose. The bulk conductivity of the PS/Ag composites increased from 1.16 S/m to 3.57 x 10(4) S/m, corresponding to a shell thickness of 35-198 nm. The PS/Ag composite microspheres with diameters of ca. 3 mu m might have great potential to be used as fillers in anisotropic conductive films because of the uniform diameter, low density and good conductivity of the microspheres. (C) 2012 Elsevier B.V. All rights reserved.