My program of research over the next 4 years will continue to focus on better understanding how neighborhood built and social environments influence obesity and related behaviors in youth. The foundation of my current program is based on my two first major grants, the Residential and School Studies, both complementary to the QUALITY cohort. These studies aim to identify attributes of children¿s residential and school neighbourhoods that influence weight and lifestyle behaviours in children. Over the next four years, ongoing research activities using data from these studies will be completed. In addition, data from the first follow up visit of the QUALITY cohort will be available in January 2012 allowing for analyses exploring how neighbourhoods influence changes in weight and lifestyle behaviours over time. For the 3rd QUALITY cohort visit three additional grants are planned: 1) the School Transition Study, to assess the impact of transitioning from elementary to secondary school on weight and related behaviours; 2) the Social Networks and Obesity Study to examine whether obesity ¿spreads¿ through social ties; and 3) the Neighbourhood Evolution study to provide insight on the impact of change in neighbourhood exposures on status and lifestyle behaviours. Moreover, I have enriched my program by broadening the scope of neighbourhood environment exposures and health outcomes with a new grant (under review): ¿Influence of neighbourhood characteristics and obesity on asthma outcomes in children and adolescents¿. Here I propose to identify neighborhood features (air pollution, built and social environment) that relate to asthma control. This exceptional and ambitious program of research will yield important contributions and help us understand the nature of spaces and settings that influence children¿s health and well-being. Findings will be useful to inform neighbourhood-level interventions, support clinical interventions and guide health policy, ultimately resulting in improved health of youth.