Abstract: In his article Iliasov touches upon particular theoretical and practical issues and rules of tacit admission aimed at improving competiteveness in arbitral proceedings. He analyzes the provisions of Part 3.1 of Article 70 of Arbitral Procedural Code of the Russian Federation that allows the court to recognize circumstances the other party refers to in order to prove their requirements or complains in case these circumstances have not been contested or disputed or other proofs of their disagreement. The research methodology includes general research methods such as analysis, synthesis, generalisation, analogy and special research methods (formal law). As a result of the research, the author concludes that the aforesaid novella is an example of inconsistent changes of arbitral proceedings that may lead to the impairment of rights of participants. The practical importance of the research is that the results can be used to prepare legal acts in the field of the procedural law.