Size-controlled synthesis of metal nanostructures has opened many new possibilities to design ideal building blocks for future nanodevices. By solution-based method, silver triangular nanoprisms of different sizes (edge length) have been synthesized. First hyper-polarizabilities of silver triangular nanomaterials were measured using hyper-Rayleigh scattering technique. We have shown that both linear and nonlinear optical properties are highly dependent on the size of silver triangular nanoprism. We provide experimental evidence for higher multipolar contribution to NLO response of silver nanoprism. (C) 2009 Elsevier B.V. All rights reserved.