The Battle of Cer was fought between Serbia and Austria-Hungary. It was a battle during the Serbian Campaign in the World War I. This battle was fought in August 1914. The place of the battle was near Cer Mountain and town of Šabac. The Battle of Cer started on 15 August. It was a battle in the first Austro-Hungarian invasion of Serbia. On the night of 15 August, soldiers of the Serbian 1st Combined Division encountered enemy outposts that were established on the Cer Mountain, in earlier stages of the invasion. This encounter escalated into a battle. The goal of the Austro-Hungarian forces was control over town of Šabac and surrounding villages.
On 19th of August, Austro-Hungarian soldiers lost their moral. Many of them returned to their country, but many soldiers drowned in Drina, because they were in panic. 5 days later, on 24 August, Serbian forces entered Šabac, again, and take over the control. This was the end of the battle.
Both sides had massive losses. According to Jordan, Austro-Hungary lost 37.000 soldiers. 7.000 were fatalities. Misha Glenny claimed that Austro-Hungary lost between 6.000 and 10.000 soldiers. 30.000 soldiers were wounded. According to Horne, Austro-Hungary lost 8.000 soldiers, and 30.000 were wounded. They also lost 30 machine guns, 46 cannons and 140 ammunition wagons. David Stevenson, a historian, said that 4.500 soldiers were taken as prisoners.
On the other side, loses of Serbian army also vary. Both, Jordan and Horne claimed that Serbia lost 3.000 soldiers and that 15.000 were wounded. According to Glenny, between 3.000 and 5.000 soldiers were killed. After the battle, both sides were weakened.