The presence of two opposite specialist’s participation models used by the domestic legislator in three existing civil procedural codes demonstrates the competition of the adversarial principle implementation approaches in the civil procedure. The doctrinal assessment of each model of the specialist’s involving to the litigation is also ambiguous. This resulted, notably with the Plenum of the Supreme Arbitration Court «blessing», in the development of the practice of applying in the arbitration process the model enshrined in the Code of Civil Procedure of the Russian Federation, which gives rise to some kind of curiosity: the court calls the specialist not on its own initiative, in accordance with art. 87.1 of the Arbitration Procedure Code of the Russian Federation, at the request or with the consent of the parties, that, in particular, seems unacceptable in the specialized arbitration court, where an adviser from the apparatus of the same court can be called as a specialist. The question of the balance between public and private law elements of the adversarial principle has traditionally been the subject of doctrinal discussions. The article concludes that the implementation of the adversarial principle in the arbitration process is achievable only in combination with judicial guidance of the process, and the call of a specialist is possible only on the initiative of the arbitration court, taking into account the opinions of the persons participating in the case.