Gender mainstreaming developed as the global strategy for gender equality nearly two decades ago. Since then it has faced criticism for its technocratic application, and its role in the de-politicisation and neutralisation of the women's movement in gender policy-making. In the health sector, this incongruity is exacerbated by a traditional bio-medical approach to women's issues. In this paper, we ask whether gender mainstreaming can be made to work in the health sectors of developing countries where these challenges, as well as women's poor health status, are further complicated by a raft of local traditional, cultural, political and socioeconomic barriers. To answer these questions, we present a case study of Papua New Guinea (PNG), one of the world's most disadvantaged and politically challenging countries. We review data on women's health in PNG and analyse PNG's aspirational and actual performance on gender mainstreaming, looking at: international commitments; political will and capacity; national policies and programmes; and the women's movement along with civil society's participation. We find numerous paradoxes between the aims of gender mainstreaming and the necessary conditions for its success.