The adoption in October 2000 of UN Security Council Resolution 1325 on Women, Peace and Security is regarded as a groundbreaking achievement in putting women's rights on the peace and security agenda of the UN. Critics have suggested that the adoption of this resolution has made little difference in terms of changed policies and practices. I argue, however, that it has nevertheless made a difference. The adoption of Resolution 1325 is the expression of a new norm in the making. Furthermore, it illustrates how cross-cutting thematic issues such as “women, peace, and security” today are placed on the agenda and nurtured by the UN Secretariat in close cooperation not only with member states, but, just as important, with networks of nongovernmental organizations and individual experts.