Abstract: Since the nineties more attention has been paid to the gender dimension in development. Through the 1995 Being Declaration and Platform for Action and various policy documents of the OECD/DAC the shift from a Women in Development (WID) approach to a Gender and Development (GAD) approach has been internationally spread. Within the GAD approach the need to integrate a gender dimension in all different phases (diagnosis, planning, implementation, budgeting, monitoring and evaluation) (= vertical gender mainstreaming) of interventions in different sectors (=horizontal mainstreaming) is emphasised. In line with the 1995 Being Declaration and Platform for Action and similar to the majority of bilateral and multilateral donors, Belgium has adopted a gender mainstreaming strategy. In order to take stock of and analyse the effective implementation of the gender mainstreaming strategy and its effects on the ground, the Belgian´s Special Evaluation Office of International Cooperation has recently (July 2013) commissioned an evaluation. The focus of the evaluation is both on headquarters and a selection of five case study countries. This working paper presents a selection of the first findings of the head quarters evaluative exercise and identifies several strengths, weaknesses, opportunities and challenges.