BIG is a project for the promotion of physical activity among women in difficult life situations. Following the main health promotion principles of the WHO, the women shall be enabled or empowered to take control of determinants of their health. A comprehensive participatory approach was applied and women were included in planning, implementing and evaluating the project. For measuring the effects of BIG on the empowerment of participating women, qualitative semi-structured interviews with 15 women participating in BIG were conducted. For data analysis, qualitative content analysis was used. Results showed the empowerment of the women on the individual level as they gained different competencies and perceived self-efficacy. These effects were supported through the empowerment process on the organizational and community levels where women gained control over their life situations and over policies influencing them. Therefore, the participatory approach of BIG is a key success factor for empowerment promotion of women in difficult life situations.