BACKGROUND: Asthma burden in the US is not evenly distributed. Although asthma prevalence varies widely across urban neighborhoods, little attention has been paid to the community as a key contributor. OBJECTIVE: To determine the effect of positive socio-environmental community factors on childhood asthma prevalence in Chicago. METHODS: From 2003 to 2005, an asthma screening survey was conducted among children attending Chicago Public/Catholic schools from kindergarten through eighth grade. One hundred five schools participated, yielding a stratified representation of 4 race-income groups. Positive community factors, such as social capital, economic potential, and community amenities, were assessed by using the Metro Chicago Information Center's Community Vitality Index. RESULTS: Of the surveys returned, 45,177 (92%) were geocoded into 287 neighborhoods. Neighborhoods were divided into quartile groups by asthma prevalence (mean, 8%, 12%, 17%, 25%). Community vitality (54% vs 44%; P < .0001) and economic potential (64% vs 38%; P < .0001) were significantly higher in neighborhoods with low asthma prevalence. Neighborhood interaction (36% vs 73%; P < .0001) and stability (40% vs 53%; P < .0001) were significantly higher in neighborhoods with high asthma prevalence. Overall, positive factors explained 21% of asthma variation. Childhood asthma increased as the black population increased in a community (P < .0001). Accordingly, race/ethnicity was controlled. In black neighborhoods, these factors remained significantly higher in neighborhoods with low asthma prevalence. When considered alongside socio-demographic/individual characteristics, overall community vitality as well as social capital continued to contribute significantly to asthma variation. CONCLUSION: Asthma prevalence in Chicago is strongly associated with socio-environmental factors thought to enrich a community. A deeper understanding of this impact may lend insight into interventions to reduce childhood asthma.