The article discusses various aspects of the cooperation between the Polish intelligence service and the Czechoslovak 2nd Division in the interwar period. Their contacts primarily consisted of exchanges of information about Germany, and to a lesser extend about the Soviet Union. They represent a backstage for the founding and activities of the Polish military intelligence service office in Prague, which passed along messages while also tracking the Ukrainian emigration during the period of the First Czechoslovak Republic. Cooperation between the intelligence headquarters was maintained even though Poland and Czechoslovakia had political and military opinions at variance. The article systematizes, clarifies and elaborates the information that been available to date on this subject.