The subject of the study is the legal regime of testamentary burden (legacy) in relation to immovable property, particularly residential premises, as one of the most complex and conflicting institutions of inheritance law. The research focuses on the interaction between heirs, legatees, and other participants in inheritance relations during the execution of the testator’s will. The study employs formal-legal, comparative-legal, and systemic methods to identify contradictions between the principle of testamentary freedom, heirs’ property rights, and housing legislation guarantees. The article substantiates the dual legal nature of testamentary burden, combining features of both obligation and property law, which creates difficulties in law enforcement and judicial interpretation. Judicial practice is analyzed, revealing inconsistent qualification of testamentary burdens and the lack of uniform standards for protecting the rights of legatees and heirs. The results highlight key problems in law enforcement and propose legal solutions to ensure a balance of interests and the effective fulfillment of the testator’s will.