 He took part in the decision to begin the Warsaw uprising.Five weeks into the Warsaw Uprising, on 4 September 1944, Pełczyński was gravely wounded when the "PKO" savings-bank building on "Świętokrzyska" Street was bombed, and as a result he could no longer carry on the duties of Home Army chief of staff.After the suppression of the Uprising, Pełczyński was imprisoned by the Germans at the Langwasser camp, then at Colditz.