This article attempts to assess the United Nations Peacebuilding Commission’s (PBC) work during its inauguration phase, which was accompanied by high expectations. It sketches the central steps in the development of the PBC, explains its organizational structure and tasks, and evaluates the effectiveness of the measures that have been implemented to date. Our specific focus is on the UN’s learning capacity and the opportunities for improved coordination of peacebuilding missions. The analysis finds that the PBC has achieved more than could have been expected considering its inadequate financial and personnel resources. Nevertheless, to fulfill its mandate, a greater integration of all relevant actors is necessary, as is the securing of technical capacities and financial support. Just as important is a systematic accounting of the many and varying ‘lessons learned’ in the area of peacebuilding as well as the establishment of ‘institutional memory’.