The monograph reveals the legal essence of the powers of the appellate court to review court decisions on appeal in the criminal proceedings of Ukraine, clarifies the concept of "powers of the appellate court", divided and classifies the powers of the appellate court to review court decisions on appeal order in criminal proceedings, their functional purpose and mechanism of implementation are revealed. Legislative regulation and practice of application of powers of the court of appellate instance at different stages of appellate proceedings are analyzed. The main factors determining the limits of the appellate court's powers to review court decisions have been studied: the limits of the appellate review, the rules on the inadmissibility of "turning for the worse", the grounds for appealing to change or revoke court decisions. Proposals and recommendations aimed at improving the legal regulations and practice of applying the powers of the appellate court to review court decisions on appeal in the criminal process of Ukraine. adjuncts, students, cadets, students of higher educational institutions of legal profile and all those who are interested in appellate review of court decisions in the criminal process of Ukraine.