Adult lesbians are not sufficiently physically active to achieve physical and psychological health benefits. Lesbians are one of the least understood minority groups. Therefore, the purpose of this study was to use an ecological framework to identify factors internal to individuals and present in their social environments that may impede participation in regular physical activity. Twenty-one self-identified lesbians aged 22 to 61 years participated in one of four focus groups. The lesbian participants reported many general barriers (i.e., obstacles to participation regardless of sexual orientation) similar to previous research with other populations of women, not stratified by sexual orientation, such as being too tired and the lack of a physical activity partner. A number of lesbian-specific barriers (i.e., obstacles unique to being a lesbian) were also identified, such as the lack of lesbian-focused physical activity groups and the lack of same-sex family memberships to fitness facilities. In conclusion, for many of the general barriers, some of the proven and effective traditional intervention strategies are likely to be effective in increasing physical activity participation rates in the lesbian population. However, barriers related to sexual orientation are likely deeply entrenched in the socio-cultural system of American society and require a societal rethinking of attitudes towards lesbians, a cultural change that is not as easily amenable to traditional health promotion interventions. [ABSTRACT FROM AUTHOR]