Purpose: Examine the contextual effects of neighborhood built and social environments on exercise. Design. Cross-sectional, multilevel study. Setting. City of Chicago. Subjects. A probability sample of Chicago adult residents (response rare = 55%) Measures. The exercise measures were based on. two questions: "How often a week on average do you work out or exercise?" (N = 3530) and, "Did you exercise regularly in the last year?" (N = 907). Neighborhood social environment was measured by socioeconomic and social capital indicators. Neighborhood built environment was captured, by pedestrian injury rate, residential density, distance to subway or parks, land use mix, and access to neighborhood amenities. Analysis. Random, effects logit and multinomial models. Results. For weekly workout/exercise, individuals with access to restaurants and bars were more likely to report one to three times of weekly exercise (OR = 1.08; 95% CI: 0.99, 1.19) and four times or more weekly exercise (OR = 1.14; 95% CI: 1.03, 1.26.) compared with those who reported no weekly exercise. For regular exercise ill the past year, access to restaurants and bars (OR = 1.24; 95% CI: 1.05, 1.46) and neighborhood social environment. (OR = 1.37; 95% CI: 1.11, 1.69) were significant. The social environment effects were stronger for women. Conclusions. Neighborhood social and built environments are, both important for exercise independent of an individual's background. (Am J Health Promot 2009,-23[4]:247-254.)