INTRODUCTION: In an increasingly urbanized world, cities are a key focus for action on health and sustainability. The Sustainable Healthy Urban Environments (SHUE) project aims to provide a shared information resource to support such action. Its aim is to test the feasibility and methods of assembling data about the characteristics of a globally distributed sample of cities and the populations within them for comparative analyses, and to use such data to assess how policies may contribute to sustainable urban development and human health. METHODS: As a first illustration of the database, we present analyses of selected parameters on climate change, air pollution and flood risk for 64 cities in the WHO European Region. RESULTS: Under a high greenhouse gas emissions trajectory (RCP8.5), the analyses suggest damaging temperature rises in European cities that are among the highest of any cities in the global database, while air pollution (PM2.5) levels are appreciably above the WHO guideline level for all but a handful of cities. In several areas, these environmental hazards are compounded by flood risk. DISCUSSION: Such evidence, though preliminary and based on limited data, underpins the need for urgent action on climate change (adaptation and mitigation) and risks relating to air pollution and other environmental hazards.