THIS RESEARCH PAPER examines the threat posed by transnational organised crime to governance and security in Europe and the links between organised crime, corruption and illicit arms trafficking.Responses relevant to the problems of illicit arms trafficking and organised crime range from conflict prevention and economic development to community policing and education.However, the focus of this paper is on the law enforcement response, and the challenges that European Union (EU) enlargement will bring.Although a number of institutions, at the national, regional and international levels, are addressing various aspects of organised criminal activities, European police co-operation to combat transnational organised crime, and in particular the involvement of criminal organisations in arms trafficking, has tended to be accorded a low priority by European law-enforcement organisations. Saferworld sees the proposed enlargement of the EU to include new member states from Central and Eastern Europe as a valuable opportunity to raise awareness of illicit arms trafficking and organised crime and to develop and implement practical measures to tackle these related issues.