The article touches upon the connection between the upper chambers of bicameral parliaments and the strengthening of the principles of parliamentary system. The author draw attention to the institutionalization of modern bicameral parliaments and their functional purpose, including through the implementation of parliamentary diplomacy. Examination of examples of the Russian, Kazakh and French parliaments is carried out to test the hypothesis that an open way of forming upper chambers contributes to the greater political weight of the bicameral parliament. At the same time, the active participation of the parliament or one of its chambers in the implementation of the foreign policy of the state contributes to the growth of the importance of the institution in the political system