The article is devoted to the new historical and political investigations on the Poland in regard to Lithuania’s admission into European structures during last decades. The Polish state authorities took part at generation of actual political events of independence receiving in Baltic States in memorable 1991 year. As an important part of the background for the States strategic partnership it is possible to admit the collaboration in the developments of economical and industrial units, which reached the high point of its intensity in the middle 1990, having the possibility to use the positive results of free market since January 1, 1997. The important element in the positive process in normalizing relations between Poland and Lithuania was the forthcoming political support to join NATO for all Baltic States from the Polish State side. The Polish support for Lithuania to join NATO as well as EU was consistent, principled, and made non-conjuncture way.