Silver nanowires have been successfully synthesized via a simple solvothermal method by adding sodium sulfide (Na2S) into the solution. The Ag2S Colloids produced in the initial stage help reduce the concentration of free Ag+ ions in the initial formation of silver seeds and subsequently release Ag+ ions to the solution. Otherwise, there is no oxidative etching owing to the absence of oxygen. In these cases, silver nanowires are grown preferentially. Furthermore, silver nanowires with adjustable diameters can be obtained by adjusting the concentration of Na2S. Electron Microscopy, X-ray diffraction, and absorption spectra have been used to investigate the products, and a mechanism is proposed to interpret the controlled synthesis of silver nanowires. Finally, our results indicate that this approach provides a versatile route to prepare silver nanowires with controllable diameters. (C) 2009 Elsevier Inc. All rights reserved.