The completion of the Single Market and the introduction of the single currency are transforming Europe from a group of separate economies into an integrated economic entity.This new economic framework will make the interplay between social and economic policy even more important.This paper attempts to provide some observations and analyses of the changing social policy in EU member states with the European integration process.What kind of changes have emerged and will emerge in Nordic welfare model due to the start of the single currency Euro?Is there any potential possibility that the legitimacy of the welfare state will be challenged essentially?In which way the social security systems in EU member states try to cope with the fiscal problems and are there any trends towards a common European way of financing?Questions like these are confronted in this essay.