This diploma thesis deals with the Czech regulation of criminal liability in the area of environmental protection. Apart from provisions of Title VIII of Second Part of the Criminal Code, the thesis also discusses other facts-of-the-crime definitions that are not included in this title, but are relevant for the protection of environment, and certain other issues concerning the general provisions of criminal law, including the criminal liability of legal persons. The thesis also focuses on legislation falling outside the scope of criminal law that can serve as a basis for determination of illegality of these acts.