This paper examines the extent to which gender mainstreaming is constitutionally embedded in the legal framework of the European Union. Within the framework of that broad question it examines three sub-questions concerning the robustness and constitutionalised nature of the E.U.'s `equality regime', the extent of adaptation to mainstreaming methodologies by supranational institutions such as the Court of Justice, and the extent of the gender dimension in the debates which are shaping the future of the European Union, especially the 2002–3Convention on the Future of the Union and the Commission's Governance White Paper of 2001.The E.U. is analysed in this article as an emergent, non-state, postnational constitutionalised polity. The first section presents this perspective, and the succeeding three sections engage with the three` sub-questions' outlined above. The conclusion suggests that as yet, while gender concerns maybe constitutionally embedded in the Treatyframe work, they are less prominent in the constitutional politics of the Convention and the Governance White Paper.