The paper is devoted to the eastern dimension of Poland’s foreign policy. The theoretical basis of Poland’s foreign policy is the issue of main concern. Polish role in the expansion of Euro-Atlantic institutions is revised when the author examines the historical and theoretical roots of current Polish geopolitical doctrine. The different forms of Jagellonian paradigm in Polish geopolitical thought are studied to explain their manifestation in Poland eastern policy after the 1989. Their origins, theoretical explications and forms of manifestation are described and analyzed. The article reveals their influence on the development of Atlanticist geopolitical vector in modern Poland, describes and explains its eastern policy.