ENThe article describes the history of practice and organization of the High Tribunal, the highest judiciary unit, called according to the tradition of Middle Ages grand principality of Lithuania. It was found in December, 1918 and functioned under this name till the Soviet occupation. In the beginning, the organization and functioning of the Tribunal was arranged under the so-called Temporary Act of Judiciary Practice and Organization of 1918, which later on was substituted by the new Judiciary Act of 1933. The latter act divided the history of the institution mentioned above into two periods. The former act described the High Tribunal as an appeal instance for the cases tried in the courts of the middle unit (district courts). The later appendices of this act also delegated the limited cassation towards some cases tried by general competence courts and military courts. However, since a great amount of cases did not reach the Tribunal, the possibilities of law interpretation function were not fully benefited. According to the second Judiciary Act, the High Tribunal was released from the appeal function, which was referred to the newly established judiciary unit, therefore, the High Tribunal turned into the court of appeal for the cases tried by the general competence courts, military competence courts and the courts of Klaipeda region. There were developed and regulated the possibilities of law interpretation and application equalization as well as setting the distribution of cases and some functions of administrative court. It remained the trial of cases brought against the President of the Republic and the members of government for high treason and malfeasance as the first instance.The article describes the structure, practice organization and statistical data on practice load analyzing the complaints against the decisions of the lower courts as well as the practice on law interpretation of the Tribunal, which was regarded as one of the most important functions of the Tribunal. [From the publication]