The full-scale invasion of russian troops caused the immergence in Ukrainian criminal legislation of new rules, aimed at raising the effectiveness of combating this military aggression. Among these rules one of the key ones is the article 43.1 of the Criminal Code of Ukraine, regulating the combat immunity. The research paper’s objective was the development of some suggestions concerning interpretation of combat immunity and the improvement of its regulation under Ukrainian criminal legislation. While conducting this research the authors used in particular the following methods: gnoseological, systemic-structural, dialectical, logic-semantic and comparative-legal. Some proposals to improve regulatory framework of circumstances excluding criminal illegality of action stipulated by the Criminal Code of Ukraine were elaborated, as well as interpretation of its some attributes. The suggestion was to exclude the definitions of “ammunitions” and “explosive materials” from the text of the Criminal Code of Ukraine, because under their content they are covered by the understanding of concepts “weapon” and “armament”. It was found that when repelling and deterring armed aggression of the russian federation or aggression of another country, it is permissible to use not only armed force, but also any other force capable of striking the enemy, and it is important that such use complies with the rules of international humanitarian law. They emphasised that actions of military personnel or civilians who used poison or other items or weapons prohibited by international humanitarian law to repel and deter the armed aggression of the russian federation, despite the fact that their actions were aimed at countering the occupiers, are subject to criminal liability under Criminal Code of Ukraine. The authors suggested to seek ways of legal possibility to use stricter, except treacherous ones, means and methods of conducting war against armies of those countries, whose armed forces do not absolutely respect rules of international humanitarian law during warfare. The practical value of this work lies in the fact that its results can be used in further research on combat immunity in criminal law, as well as in the application of certain provisions of the Criminal Code of Ukraine in the practical activities of law enforcement agencies