During the German invasion of Poland which started World War II in September 1939, it was the site of the Battle of Jarosław, after which Germany captured the town. Shortly afterwards the German "Einsatzgruppe I" entered the town to commit various atrocities against the population. Under German occupation, the town was part of the Kraków District of the General Government. The Polish resistance movement was active in the town, and since May 1940, underground Polish newspaper "Odwet" was distributed in Jarosław. In 1944, the town was captured by the Red Army and then restored to Poland, although with a Soviet-installed communist regime, which remained in power until the Fall of Communism in the 1980s. Some local Polish resistance officers were arrested by the Soviets and then imprisoned in a Soviet camp in Trzebuska. The communists expelled most of Jarosław's Ukrainian population, at first to Soviet territories and later to territories regained from Germany.