Introduction In recent years epidemiologists have recognised the impact of the physical and social environment on populations' health. To measure the social and physical characteristics of a neighbourhood is one of the more important conceptual, methodological, and operational challenges for the incorporation of such information in epidemiological studies. The number of instruments that use the systematic social observation (SSO) has been growing in recent years, with variations in the objective, target population and data collection methods. The design and implementation of studies using SSO in developing countries like Brazil is challenging, since most of the cities have disordered areas of occupation and high levels of violence. Most SSO tools published to date evaluate specific aspects of neighbourhoods. The Observatory for Urban Health/Epidemiology Research Group propose a broader toll for SSO, covering different aspects of the neighbourhood, which makes it possible to study several outcomes in the context of urban health.

Methods The instrument contains seven domains: physical, social and physical activity, characterisation of properties, aesthetic, services, safety and measurement of thoroughfare. The sample includes 1036 streets segments of 149 census tracts in the city of Belo Horizonte, Brazil. The study area is characterised by heterogeneity in demographic, socioeconomic and health indicators. Data collection will be finished until May 2011.

Results and Conclusion The methodology of the data collection—including details of the logistics and of instruments for data collection—and the main results will be presented.