During World War II, Šamac was included into Nazi-controlled Independent State of Croatia (i.e. the NDH).

The town lies on an important strategic position – the corridor connecting western and eastern parts of Republika Srpska. In the early stages of the Bosnian war the town was taken by Serbs who established the provisional municipal government.

Most Bosniaks and Croats fled the town. In 2003, three town leaders at the time were sentenced in ICTY for crimes against humanity. During the war, a semi-permanent front line was established against Croatian and Bosniak forces towards the neighboring Orašje.

As with most other places under their control, Serb leaders removed the "Bosnian" adjective from the town's official name. Bosniaks and Croats continue to refer to it as "Bosanski Šamac".