European civil procedural law excludes social security from its scope without defining the matter. The concept is subject to an autonomous interpretation aimed at ensuring the effectiveness of Union law in the field of coordination of social security systems. It is accepted in the case law of the CJEU that the substantive content of the concept of social security is determined by the material scope of application of Regulation (EU) No 883/2004. Matters that are not covered by the coordination of social security systems remain outside the scope of this exclusion. With regard to them, assessment of the application of the norms of European civil procedural law requires consideration of the concept of civil and commercial cases. Only by considering both concepts of "civil and commercial cases" and of "social security" — it is possible to determine the scope of the social security exclusion in European civil procedural law.