Most current environmental challenges have their origins in urban areas, but it is also these same urban areas that bring together the commitment and innovation needed to resolve them. In recent years, the EU has sought to explore ways in which urban and environmental policies can be integrated in order to promote and develop sustainable cities. There is no universally accepted definition of a ‘sustainable city’. However, the concept tends to be essentially characterised by the ability to make development choices which respect a good balance between economy, ecology and equity. Over time, the EU has elaborated a wide range of strategies and initiatives (URBAN, URBACT) and sustainable development has been ‘mainstreamed’ into a wide range of policies. The pivotal role played by local authorities and citizens has in many cases been instrumental in creating permanent networks (Covenant of Mayors) or raising awareness (sustainable public procurement). The EU supports the development of sustainable cities through a range of funding opportunities including the Structural Funds, LIFE+ and the Framework Programme for Research and Development. The EP has set up the URBAN Intergroup to ensure that urban-related issues are reflected in EU legislation.