The rapid urbanization of the world has had profound effects on global biodiversity. The increasing number of people living in cities and towns, coupled with the magnitude and intensity of human activities has resulted in significant impacts for local, regional and global environments. The creation and expansion of cities produces new types of land-cover and environmental conditions. These changes in land use and land cover result in native habitat loss and landscape fragmentation, toxification of the biosphere, loss of ecosystem function, the introduction of exotic species, and the loss of native species. The predicted increases in the number and size of human settlements, especially in developing countries, over the next 20 years, coupled with the predicted changes in climate has created an unprecedented call for scientific information to guide management strategies and mitigation options to create sustainable and habitable cities and towns for the future. Despite recognition for the importance of urban biodiversity by the Convention of Biological Diversity and an emerging base of science on the biodiversity of urban areas, a general synthesis on biodiversity is in a fledgling state. A comparative approach to urban biota is needed to produce comparable methodologies to understand, preserve, and monitor biodiversity in cities. The design and construction of urban infrastructure can create novel habitats for plants and animals that can supplement remnant habitats for species and communities in cities and towns, or that can provide habitat that has been destroyed in a region due to human development of the landscape. This symposium will bring together an international group of urban ecologists to identify: 1) global patterns of biodiversity within and across cities; 2) their environmental and social drivers; and 3) opportunities for using ecological knowledge to develop effective biodiversity management, restoration and planning strategies. The symposium will be structured into two parts. The first will address the patterns and drivers of biodiversity within and across cities in order to provide a general synthesis of biodiversity. The second part of the symposium will address design and planning of cities for biodiversity from the micro-scale (green roof ecology) to the city-scale.