This UNDP Practice Note is a contribution to a wider UN effort to enhance cooperation and improve effectiveness in the area of disarmament, demobilization and reintegration(DDR) of ex-combatants. This Practice Note defines DDR and outlines UNDP’s role in the process. It reflects on lessons learned from previous UNDP DDR programmes, and offers practical guidance for DDR policy makers and practitioners, providing a framework for future UNDP interventions in the field.