The Constitution of the Republic of Croatia and the law regulate the activity of bodies of local and regional self-government units. When performing jobs of local and regional importance, priority should be given to those offices closest to the citizen, while respecting the principle of subsidiarity. These are the representative bodies of the local and regional self-government units, which are making decisions and other general acts for regulating numerous social issues. They allow easier law enforcement or just supplementing legal acts. These are very important acts, and the power to decide about them is regulated by a legal norm. The main task of representative bodies is to adopt general acts, which create new legal rules and which are prescribed by the law according to the Constitution of the Republic of Croatia. The Constitution of the Republic of Croatia declares the principle of constitutionality and legality of regulations. All enactors of normative acts, including the representative bodies of local and regional self-government units, have the obligation to obey to the principles of constitutionality and legality. In practice, deviations from the principles are possible and the representative bodies of local and regional self-government units may adopt a general act which are not in a full accordance with the Constitution of the Republic of Croatia. For these reasons, there are mechanisms for monitoring the legality of general acts of representative bodies entrusted to different types of state administration bodies. Finally, solutions are proposed that could contribute to the efficiency and effectiveness of monitoring the constitutionality and legality of general acts of the bodies of local and regional self-government units.