Museum collections very often contain artefacts of a significant material value, which are also of great importance for the national heritage. Exhibits listed in a museum inventory belong to the capacious category of national goods, which means they are protected by law. Given the whole number of crimes against the cultural heritage, museums are certainly a group of institutions least likely to be threatened by it. However, we must not forget, that theft might happen anywhere; even the largest and perfectly safeguarded museum is not free from this type of danger. When a museum exhibit gets stolen, the following procedure shall be applied: closing all the entrances, informing the guards, checking the security devices, securing the crime scene and the whole area of an exhibition, limiting an access to the crime scene, informing the supervisors (directors), informing the police, checking all the rooms and the surrounding area, securing the monitoring system and documentation, having a police report filed, reporting the loss with the description for putting it in an official data base. It seems worthwhile to take measures to increase both knowledge and awareness of museum employees on a regular basis, as well as to analyse the patterns of conduct in reference to legal regulations and existing procedures.