This volume contains the proceedings of the IUTAM Symposium on Mechanical Behavior and Micro-mechanics of Nanostructured Materials, held in Beijing on June 27-30, 2005. The proceedings consist of approximately 30 presentations. Nano-scale, micro-scale, theoretical, experimental and numerical aspects of the subjects are covered. A wide scope of research and progress are displayed. This is the first work in print on this particular subject.