ENThe article presents the status of research on the activities of Lithuanian civilian authorities and the Lithuanian police with regard to Polish-Lithuanian relations, in the period of diplomatic contacts stabilisation since 1938 till the end of 1939. Analysis of available Polish and Lithuanian historiography shows that this specifi c area was only superfi cially treated by researchers, unlike diplomatic and military issues. As for times on the eve of WWII, civilian authorities and national policing issues had been explored only if related with the fact of establishment of diplomatic relations between Poland and Lithuania. As for the period after September 1939, the article focuses on elements related with extending the Lithuanian administration onto the Vilnius Region. Key words: Lithuania, Poland, administration, Polish Military September Campaign 1939. [From the publication]