An easy one phase synthesis of monodisperse silver nanoparticles and their self-assembly has been reported. Thermal decomposition of silver acetate in diphenyl ether in the presence of oleic acid (cis-9-octadecenoic acid) and oleylamine (cis-9-octadecenoic amine) leads to the formation of silver nanoparticles. The amount of organic content present on the surface of Ag nanoparticles affects the self-assembly of nano particles. In the presence of oleic acid alone, no self-assembly was observed but the presence of oleyl amine along with oleic acid led to increased organic coating on the surface of silver nanoparticles resulting in the self-assembly (cubic or hexagonal) of monodisperse silver nanoparticles. The silver nanoparticles were characterized by powder X-ray diffraction (XRD), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), CHN analysis, transmission electron microscopy (TEM), selected area electron diffraction (SAED) and UV-visible spectroscopy. (C) 2010 Elsevier B.V. All rights reserved.