This book constitutes the thoroughly refereed post-conference proceedings of the Third International Conference on Nano-Networks, Nano-Net, held in Boston, MS, USA, in September 2008. The 17 revised full papers presented together with 5 invited presentations were carefully reviewed and selected. The papers address the whole spectrum of Nano-Networks and spans topis like modeling, simulation, statdards, architectural aspects, novel information and graph theory aspects, device physics and interconnects, nanorobotics as well as nano-biological systems.