The article is devoted to a specialist in a certain branch of knowledge as a subject of proof in the context of reform of the civil procedural legislation of Ukraine. Separate provisions of the civil procedural legislation that regulate the possibility of a specialist’s participation in a certain branch of knowledge when providing certain conclusions to the court, at the stage of research and evaluation of evidence, are analyzed. The legal nature of the concepts «special knowledge» and «special knowledge» is disclosed. The approaches for determining the legal status of persons with special knowledge are indicated. The regulatory and procedural obstacles and prerequisites for the participation of a specialist in a certain branch of knowledge as a subject of proof in the civil process are revealed. The article analyzes judicial practice in civil cases on the chosen problems of the study. Ways and suggestions are proposed to improve the CCP of Ukraine in the context of reform of civil procedural legislation.