[en] A simple synthesis of Ag nanostructures such as nano rods and nano wires has been demonstrated with citrate-capped Pt seeds. UV-visible spectra and photographs of the synthesized solutions at different UV exposure times showed that the citrate-capped Pt seed played a crucial role in the growth of Ag nano structures. After UV exposure of the colloidal solution for 60?min, the average diameter, length, and aspect ratio of the Ag nano structures were about 95 nm, 2.1μm, and 22, respectively. The photochemical reduction is hypothesized to result from photoelectron transfer from adsorbed citrate to Pt nanoparticle seed allowing Ag ions to form Ag nano structures. Based on X-ray diffraction spectra and transmission electron microscope images, the synthesized Ag nano structures were a face-centered cubic single crystal with good purity. These results suggest that the photochemical reduction method can provide Ag nano structures in the presence of citrate-capped Pt seeds at room temperature for anisotropic Ag products