PURPOSE: The purpose of this study was to identify exercise environments and social support associated with exercise behaviors in middle-aged women. METHOD: Subjects were 207 women aged between 41 and 59 yr in an urban community. The research instruments utilized in this study were exercise stages, exercise environments, exercise partners and social support scale. Subjects were given a self-report questionnaire. Data was analyzed using the SPSS Win program. RESULT: The subjects were in the stages of precontemplation (3.4%), contemplation (25.1%), preparation (40.6%), action (5.8%), and maintenance (25.1%). Subjects who engaged in regular exercise were 30.9%. The mean score of the exercise environment was 6.34. The mean score of social support was 21.28, and 65.7% of subjects had exercise partners. The score of the exercise environment was significantly associated with the exercise stage (p=.01). The number of exercise partners of regular exercise groups was significantly greater than that of non-regular exercise groups (p=.00). The score of social support of regular exercise groups was significantly greater than that of non-regular exercise groups (p=.00). The score of social support was significantly associated with the exercise stage (p=.00). CONCLUSION: Exercise environments and social support need to be considered in planning exercise programs to improve exercise behavior among middle-aged women.