The GridNets conference is an annual international meeting that provides a focused and highly interactive forum where researchers and technologists have an opportunity to present and discuss leading research, developments, and future directions in grid networking. The goal of this event is to serve as both the premier conference prese- ing best grid networking research and a forum where new concepts can be introduced and explored. After the great success of the Second International Conference on Networks for Grid Applications in Beijing, China, which was held during October 8–9, 2008, the next event was scheduled for Athens in 2009. The 2009 event featured two invited keynote speakers, ten reviewed papers, and three invited papers. The program was supplemented by forums on three key areas––a workshop on Green Grids, a workshop on Wireless Grids, and a workshop on Optical Grids. Next year event is currently being planned, and it will incorporate multiple new important emerging topics related to grid networks. December 2009 Tasos Doulamis Joe Mambretti Ioannis Tomkos Dora Varvarigou