Undercover agents are special police officers who work with a changed identity and infiltrate criminal groups where they try to expose the perpetrators or prevent commision of crimes. They are used to collect items and evidence for establishing facts in criminal proceedings only when investigations cannot be carried out in another way or it would be possible only with disproportionate difficulties. The question of the permitted scope and content of their activity is extremely important, but it is not defined by our legislation, although it is absolutely necessary. This is precisely why there is often incitement by the undercover agent, which is one of the main problems presented in this paper. Due to incitement, there is also a violation of Article 6 of the European Convention for the Protection of Human Rights and Fundamental Rights, which will also be discussed, and several cases from court practice will also be dealt with. It is very important for an undercover agent to create a good undercover identity in order to infiltrate as well as possible, but also to protect his personal safety during and after the operation. Since an undercover agent cannot be under constant supervision when conducting an action, there is a possibility that he may commit numerous abuses and even go over to the side of the perpetrator. Precisely because of all the specificities of this action, its implementation can affect the psychological health of the investigator.