Noble metal nanocrystals (NCs) have become one of the hottest fields in nanoscience due to their unique/strong interactions with extra electromagnetic field, which are known as localized surface plasmon resonance. Self-assembly of noble metal NCs into the complex hierarchical nanostructures with a controllable manner could provide a promising way to obtain metamaterials with the collective optical properties and further realize their potential applications. Here we summarize the state-of-art progress in this exciting and dynamic research field, and the major challenges in self-assembly of noble metal NCs are also discussed. (C) 2012 Elsevier Ltd. All rights reserved.