Description The European thematic network ICT for energy efficiency aims at federating a wide variety of stakeholders initially from 10 European countries to develop common understanding of good practices in the field of ICT applied to energy efficiency in cities. The approach will focus on what has been done and what can be done in urban areas, places where the issue of energy efficiency is particularly crucial. The concept and reality of sustainable cities will be discussed and challenged through three working groups and the creation of a social network and best practices platform. These working groups will gather public and private stakeholders operating in the field of policy making, applied research and products conception around three topics: ICT for energy efficiency in buildings, ICT for energy efficiency in transportation and how ICT shall contribute to improved citizen behaviours regarding energy consumption. The scope of the project will therefore go from best practice promotion - i.e. selection of case studies to identify appropriate technologies to be implemented and to measure energy savings - to strategy thinking and writing with the view to contributing to the new i2010 strategy for sustainable growth.