The article analyses the content and institutional and legal framework for the coordination of social welfare systems in the European Union. Analysing documents in particular, EU Acts and Regulations, as well as taking into account modern scientific research, the material substantiates the existence of a separate area of scientific and practical activities in the European Union, namely, social welfare. It is specified that «social welfare» as a theoretical construct and direction of public policy should be considered within the concept of «social security». In a narrower context, social security can be interpreted as a basic social standard, which in most cases is implemented through social insurance. The social welfare coordination system in the European Union is quite complex and undergoing constant change. The need for modernization in view of changes in working conditions in the modern world has been updated in the period of the coronavirus pandemic. According to European Union regulations, the main areas of social welfare in the EU cover payments in connection in specific situations. Such situations are included: sickness benefits, maternity and paternity benefits, invalidity benefits, old-age benefits, survivors’ benefits, benefits related to accidents at work and occupational diseases, and benefits in connection with death, unemployment benefits, pre-retirement benefits and family benefits. The article identifies the basic principles of coordination of social welfare systems in the European Union. Among others, the most important of these is equal treatment of all people; free movement of people; unity of legislation applicable in this field in different countries; the provision that rights acquired in one country are retained in another; and the idea that insurance periods acquired in other countries summed up. In addition, the material offers a comprehensive analysis of all major EU legal acts coordinating social security systems at national levels.