After the war, along with northern Greater Poland, it became again part of Poland. The historic Polish name Krzyż was confirmed as official, and later on, the adjective Wielkopolski was added after the region of Greater Poland, within which it is located, to distinguish it from other places of the same name.
During World War II, the Polish resistance was active in the town. Feliks Kasprzak, who founded the local military and civil administration cell of the Home Army, was arrested by the Gestapo in April 1944, however, he escaped during a German-perpetrated death march in 1945.