ENThe aim of the article is to define and characterize the key premises proving that the implications of the Polish-Lithuanian dispute in 1919-1922 adversely affected the security of the reborn Polish state. The analysis was based on archival material collected in the Archives of the Józef Piłsudski Institute in America, as well as on the available literature. It was accepted that the escalation and continuation of the Polish-Lithuanian dispute had a negative impact on the security of the Polish state in the years 1919-1922. It adversely affected the position of the Polish state in various security areas. The arguments presented allow us to state that the Polish-Lithuanian conflict in 1919-1922 affected various security areas of the Second Polish Republic. It has adversely affected both the internal security and external security of the state. It concerned military threats in connection with the activities of the Lithuanian army and temporarily organized partisan units as well as boiled down to numerous non-military threats. Keywords: The Second Polish Republic, security, Lithuania, dispute, threat. [From the publication]