From 2015 Hungary has been permanently affected by the irregular migratory flow, which – already in 2015 - marked a beginning of a new era in the history of European migration. In many European countries, including in Hungary, the public opinion related to irregular migration has forced the legislators to take the necessary and effective measures against it. In Hungary, among others, criminal law has been also in focus. The first step was the construction of the physical border fence, and as a second stage, the Hungarian Parliament adopted the legal framework on its protection. In accordance with this step, new crimes were inserted into the Hungarian Criminal Code, which entered into force in 15 September 2015. These crimes - are called in the Hungarian literature as „crimes against the border barrier” – were the following: unlawful crossing the border barrier, damaging the border barrier and the obstruction on construction work of the border barrier. According to the relevant official statistical data, the number of crimes against the border barrier decreased significantly for the past few years. In contrast to it, the number of the irregular entries or attempts across the border barrier detected by the Hungarian authorities – at least according to the statistical data published by the Hungarian Police Force – are higher than the number of the criminal procedures conducted due to the crimes mentioned. Therefore, the aim of the paper is to present how the principle of „legality” is enforced by the Hungarian authorities concerning the irregular entries and what kind of conclusions can we make according to the criminal-statistical data and to the detected irregular entries. The paper – after presenting the legal background – will analyze the data mentioned above and will try to make legal conclusions and proposals in connection with the fundamental procedural principle mentioned above.