Over the last decade there have been major changes in patterns of international defence diplomacy. Defence diplomacy - peacetime military cooperation and assistance - has traditionally been used for realpolitik purposes of strengthening allies against common enemies. Since the early 1990s, however, the Western democracies have increasingly used defence diplomacy for a range of new purposes. These include strategic engagement with former or potential enemies, in particular Russia and China, encouraging multilateral regional cooperation, supporting the democratization of civil-military relations and assisting states in developing peacekeeping capabilities. This work analyses the new defence diplomacy and the policy challenges and dilemmas it poses. The new defence diplomacy runs alongside the old and there are tensions between the two, in particular between the new goal of promoting democracy and the old imperative of supporting authoritarian allies. These tensions cannot easily be resolved, but external defence diplomacy assistance is likely to play a continuing role in supporting conflict prevention, the reform and democratization of armed forces and the development of peacekeeping capabilities.