While the concept of gender mainstreaming has gained acceptance among many national and international development organizations, many obstacles are faced in translating the concept into tangible improvements in the health and well-being of women and men. This paper presents two qualitative case studies, one from Kenya and one from Uganda, of experiences of mainstreaming gender at district level; experiences which are set against the context of decentralization and sector-wide approaches (SWAPs). The conceptual framework of social movement theory, as used by Hafner-Burton and Pollack, is drawn upon to analyze the findings of both case studies. This paper has been written in conjunction with a paper by Theobald et al. which explores gender mainstreaming at national level.