Following the joint German-Soviet invasion of Poland, which started World War II in September 1939, the town was invaded and then occupied by Germany. Barcin was one of the sites of executions of Poles carried out by Germany in 1939 as part of the "Intelligenzaktion". Three Poles who were either born or lived in Barcin were also murdered by the Russians in the large Katyn massacre in April–May 1940. In 1943, the Germans renamed the town "Bartelstädt" to erase traces of Polish origin, however the historic name was restored after the German occupation ended in 1945.