In November 1931, Brig. Gen. Czesław Jarnuszkiewicz, commander of the District Corps no. I in Warsaw issued an order on the operational prevention of the Communist Party’s influencing the Army. It was addressed to information officers reporting to the Independent Information Office of the District Command of Corps no. I in Warsaw. The document was prepared in a period of intensified campaigning by branches of the Communist Party of Poland among troops of the Polish Army, in particular by the Party’s regional and district military divisions (the so-called militaries). Members of this strictly clandestine structure within the Communist Party of Poland were communist activists, trained in the USSR and cooperating with the Soviet Military Intelligence Service or NKVD. Any collected information related to the Polish Army were transferred via the domestic structures of the Communist regime to the Soviet Intelligence Service. Key passages of the documents refer to methods, forms and means of operational work. It is worth pointing out the classification of communist organizations operating in Poland in the introductory part. The published instruction is an important source to learn the forms, methods and means of operational work of the Military Counterintelligence Service of the Second Polish Republic during the 1930s.