Koordynacja zabezpieczenia społecznego w Unii Europejskiej

The topic of the paper refers to the most crucial issues related to the coordination of social security in EU and the regulations of the European Union law related to the national insurance contributions. The EU law determines fundamental principles for the coordination of social security in EU, which include a warranty for the protection of rights related to persons moving between the European Union Member States. The principles of the coordination of social security have normative nature, i.e. they are included in the European Union system of legal provisions. The most important principles are: the principle of equal treatment, the principle of the application of single legislation, the principle of counteracting a cumulation of benefits (proportionality), the principle of priority in the case of converging rights to benefits. The European Union legal regulations related to the national insurance contributions do not replace the national legislation but only supplement it at the level of the Community so as to ensure a closer cooperation between the institutions, which handle social security.