Political attitudes and activity of Thomas Jefferson, one of the founding fathers of American democracy, are described in this text. The author describes Jefferson's role in political activities of major importance for the creation of the USA: compiling the Declaration of Independence, operating the Legislative assembly of the state of Virginia and enacting the separation of the church and the state, creating the American foreign policy and the policy of Western colonization, introducing the first ten constitutional amendments as a guarantee of human and civil rights and elaborating the principles of the organization of federal government. Jefferson fought against excessive legislation on powers of central political institutions. He established the tradition of Republicans versus Federalists led by Hamilton. That opposition gave birth to the modern American two-party system. Jefferson's presidency was also significant due to the elimination of centralist and oligarhic tendencies of previous Federalist governments. The author suggests that Jefferson's political theory and practice have left a permanent mark on the contemporary theory of democratic republicanism.