In July 1942, Kazimierz Rawicz was transferred to Mauthausen concentration camp. Before his departure, he suggested to Pilecki, that he should be replaced as a leader of OW by Lieutenant-Colonel Juliusz Gilewicz, who already accepted the proposition. The preparations for the planned uprising in the camp were headed by Major Zygmunt Bohdanowski (in the camp known as Bończa). He had a perfect knowledge of the area around the camp as before the war he was an officer in the 5th Mounted Artillery Division, stationed in Oświęcim.

In each of the blocks where they were quartered, prisoner members of OW set up a framework of two-platoon ‘companies’ with a company commander on the spot. In case the struggle at the camp begins, they were supposed to draw in as many other prisoners as possible. Several blocks composed a ‘battalion’. In agreement with Juliusz Gilewicz, Pilecki reorganised the military resistance in the Auschwitz I main camp into four ‘battalions’.

Having escaped from Auschwitz in late April 1943 and having reached Warsaw in late August of the same year, Pilecki failed to obtain the consent of the AK High Command to start the battle to liberate the inmates. The High Command considered the forces of the AK units too weak to overcome the SS contingent in the camp.