The article is devoted to the study of the role and significance of legal presumptions and fictions in Russian civil procedure law. The author examines in detail the concepts of “legal presumption” and “legal fiction”, identifies the features of their content and legal functioning. Special attention is paid to the issues of qualification of norms containing legal presumptions and fictions, and the legal status of the relevant provisions of the Civil Procedure Code of the Russian Federation is analyzed (for example, parts one of Article 68 and the third of Article 79). The specific cases of application of the institutions in question in judicial practice are described, and a comparative analysis of the approaches of courts of general jurisdiction to the application of presumptions and fictions is carried out. The work is aimed at identifying ways to improve the legislative regulation of these categories, increase the effectiveness of their application in court proceedings and ensure the protection of the rights of participants in civil law relations.