Abstract: The institution of testamentary trust, which was Introduced as a result of the 2018 Russian inheritance law reform and updated with the amendments to the Civil Code of the Russian Federation coming into force in March 2022, aims to ensure the efficient and lossless succession of assets by Russian citizens. The question is raised whether the current regulation of norms describing the process of incorporation meets the criteria of reasonableness and is it capable to mediate the uninterrupted transfer of the mass of succession from the control of the deceased testator to the testamentary trust. The examination of all technical legal procedures related to the emergence of a new heir allows assessing the immediacy of succession by the testamentary trust, detecting the existing flaws in legal regulation that complicate the implementation of rights and legitimate interests of the testator and beneficiaries of the testamentary trust. There are currently no scientific research dedicated to the procedure for establishing testamentary trust from the perspective of practical implementation of all stages of this process. The scientific novelty is substantiated by the absence of law enforcement practice; the testamentary trusts are not duly registered in the Russian Federation. In conclusion, the author indicates the complicated regulation of the capability of the notary to comply with the shortest terms set for the creation of testamentary trust. The author also believe that the requirement for the filing order of receiving the affidavit of heirship by the testamentary trust is unnecessary.