The article discusses initiatives taken in the mid-1950s to examine the state of the rule of law in 1944–1956 in courts, prosecutor’s offices, Polish Army Intelligence Service and public security authorities. Attention is given primarily to the Report of the Mazur (Wasilewski) Commission, which was established as a result of an agreement between the Minister of Justice, the Minister of National Defence, and the Prosecutor General. The Commission’s task was to determine the extent of violations of the rule of law by the Supreme Military Court, the Supreme Military Prosecutor’s Office and the Military Intelligence Service. The article discusses in detail the manifestations of violations of the rule of law disclosed by the Commission, often criminal in character, as well as the specifi c conclusions with proposals of a variety of consequences for the people guilty of violating the rule of law in the aforementioned authorities. The Report fi ndings are presented against the background of the rehabilitation proceedings conducted with respect to the victims of the alleged ‘conspiracy in the army’. Also discussed are the works of two other Commissions dealing with the examination of violations of the rule of law in general courts and prosecutor’s offices. The Prosecutor General established a Commission for examining the state of the rule of law in the Prosecutor General’s Office and in the Prosecutor’s Office in Warsaw, while the Minister of Justice set up a Commission for examining the work of the so-called secret sections operating in 1950–1954 at the Ministry of Justice, in the Court of Appeal and the Voivodeship Court in Warsaw. I also present the results of the first criminal trials conducted against public security andMilitary Intelligence Service officers guilty of the application of inadmissible and unauthorized methods in the course of investigation.