The article is devoted to the new historical investigations on the Klaipėda Rebellion 1923 in the light of documents of the Department II of the General Headquarters of the Polish Army. By the decision of the victorious Entente the Klaipėda region was separated from Germany and placed under French administration. In autumn 1922 the Lithuanian political and military leaders decided to organize a rebellion in Klaipėda. Poland had no intention as well to intervene military, nevertheless observed the course of events in Klaipėda very carefully. From 1921 there was a Polish mission established in Klaipėda, possessing the rank of a consular agency. The situation in the Klaipėda region was evaluated also by Polish diplomats. From the beginning of January 1923 they provided the Polish Ministry of International Affairs with information (cryptograms, reports) relating to the course of events in the Klaipėda region. This information is still preserved in Warsaw.