The First Battle of Clusium took place in June of 82 BC during the Roman Republic's Second Civil War.

The war now shifted to Etruria where Sulla engaged Carbo's cavalry forces near the River Clanis, emerging victorious.

The battle is generally referred to as a stalemate, but the German scholar, Theodor Mommsen affirmed the following: Philip Matyszak disagrees: The next day Sulla retreated from the area, leaving Carbo behind at Clusium.

Sulla had heard that the Siege of Praeneste was threatened by a huge force of Samnites and Lucanians, who had finally decided to join Marius and Carbo.

Praeneste fell on 4 November, holding out surprisingly until all of Italy was under Sulla's direct control.