As expressed in the Constitution of the Republic of Polandof 2nd April 1997, the principle of separation of powers dictates that relations between the various authorities are based on a system of reciprocal brakes intended to ensure cooperation between these authorities and their mutual balance. The definitive introduction of the principle of separation of powers to the constitutional catalogue of political principles as a principle defining the model of the state is the most appropriate and valuable both for setting and maintaining the initiated direction of transformations in the scope of adopted normative decisions as well as for the whole political practice of the Third Republic of Poland. The purpose of this monograph is to present the legal status and the scope of powers of the legislative authorities (the Sejm and the Senate) and the executive authorities (the President of the Republic of Poland and the Council of Ministers) against the background of the principle of separation of powers, as expressed in Article 10 of the Constitution of the Republic of Poland.