Water-soluble monodispersed palladium nanoparticles of diameters 2.5, 5 and 10 nm controlled by varying the concentration of CTAB (hexadecyltrimethylammonium bromide) micelles have been prepared from light decomposition of Pd(PPh3)(4). The size and structure of these single crystalline particles have been confirmed using UN-visible spectroscopy, high resolution transmission electron microscope, energy dispersive X-ray analysis and powder X-ray diffraction methods. (c) 2006 Elsevier B.V. All rights reserved.