Impaired interethnic relations in the Western Balkan countries and the absence of multicultural policies proved to be major obstacles to stability, security and democracy in the 1990s. In attempting to identify what the security implications for enlargement are, the author argues that the EU should develop specific policies towards countries with a higher risk of ethnic tensions (e.g. Bosnia-Herzegovina) than those with no apparent potential for conflicts to re-emerge (e.g. Croatia). Further on, having claimed that the unresolved status of Kosovo and Bosnia-Herzegovina might have an impact on stability in the region, the author argues that, despite the EU’s advocacy of an individual approach towards applicant states, the Union’s relations with the Western Balkans will probably remain characterised by a more regional approach, in terms both of commonly-used patterns of accession (applying the same criteria and assessing achievements via the Stabilization and Association Process) and of the EU’s insistence on regional cooperation. The necessity of regional cooperation in the Western Balkans is emphasised, and the political, economic and social problems common to all countries in the region are highlighted. Finally, the author concludes that the EU’s insistence on regional cooperation in the region should be viewed as an incentive to addressing cross-boundary issues, and not as a threat that individual accession could be obstructed.