The article analyzes such a category as the subject of a claim, its place and role in civil proceedings. Disputes about the presence or absence of a legal relationship between the parties, about the obligations of the defendant, about the change or termination of the legal relationship are types of the subject of a claim. The authors give examples of the types and analyze the criteria for differentiating between the types of lawsuits on the subject of the claim. It is also noted that in disputes about the change and termination of a legal relationship the court realizes the exclusive powers granted by the legislator. The article puts forward two arguments about the limits of employing the types of the subject of the claim. The authors believe that there are no clear criteria for differentiating between the groups of lawsuits on the subject matter of the claim. Also, the authors find that in the practical field (in rule-making, courts) the subject of the claim is applied in general, without dividing it into groups. The subject matter of the claim, together with the existence of a dispute, affects the type of judicial proceedings. In judicial practice, there is an erroneous interpretation of the subject of the claim, which has negative consequences. The paper argues that the requirement to establish the fact of recognition of paternity should be considered in a lawsuit only within the framework of the requirement to establish paternity.