Interventions to improve physical activity levels among Latinos must take into consideration the social, cultural, economic, and environmental contexts of Latino communities. We report findings of formative assessments related to Mexican-origin women's levels of readiness, willingness, and ability to participate in regular leisure time physical activity in two diverse locations, the Texas Lower Rio Grande Valley and the South Carolina Midlands. The ENLACE project employed a Community-Based Participatory Research approach. Formative assessment activities focused on identification of community assets and resources and exploration of community members' experiences, opinions, values, preferences, and perceived needs related to physical activity. Data sources included windshield tours, walkability assessments of local neighborhoods; community inventory exercises, focus groups, and individual interviews. Barriers to regular physical activity included the dominance of work and family responsibilities, social norms, lack of social support, social isolation, environmental constraints, economics, and low levels of personal knowledge and motivation.