The Battle of Corupedium,was a battle in 281 BC between the armies of Lysimachus, ruler of Thrace and Macedon; and Seleucus I Nicator, ruler of the Seleucid Empire, including lands currently covered by modern eastern Turkey, Syria, Lebanon, Israel, Iraq and Iran.

Lysimachus was at that time the most expansive rulers in the eastern Mediterranean and this was observed with suspicion by Seleucus. However, there were family conflicts in the house of Lysimachus, which triggered this war of the Diadochi. As an old man Lysimachus established a veritable despotism and tyranny in his kingdom, where he would eliminate competitors or those he thought were. This behavior was encouraged by his second wife Arsinoe II, who was a daughter of his main ally Ptolemy I of Egypt. To get her own children as Lymsimachus successors, she directed an intrigue against her stepson Agathocles, the eldest son of Lysimachus, who had already proved to be an able commander and who was especially by the younger generation considered as a promising successor of his father. Probably around the year 287/286 BC Lysimachia was destroyed by an earthquake, which Lysimachus was interpreted as a bad omen for his future as well as for his kingdom. Arsinoe II was finally able to convince him of an alleged betrayal of his son, son in 283/282 BC, he gave his approval to the murder of Agathocles. The followers of the prince fled to the court of Seleucus, who now had the opportunity to appear as an avenger of Agathocles against the tyrant Lysimachus and immediately seized it and prepared his army for war. The political climate favored Seleucus in his plan, as just at this time Ptolemy I of Egypt died, and therefore Lysimachus could not expect help from this side.

Almost nothing is known about the battle itself save that Seleucus won the battle. Lysimachus died during the fighting. According to Memnon of Heraclea's History of Heraclea Pontica, Lysimachus was killed by a javelin thrown by Malacon, a Heracleian soldier serving under Seleucus.

Although the victory gave Seleucus nominal control over nearly every part of Alexander's empire, save the Ptolemaic Kingdom of Egypt, his victory was short-lived. After crossing the Hellespont to take possession of Lysimachus' European possessions not long after the battle, Seleucus was assassinated by Ptolemy Keraunos and Macedon swiftly became independent once again. It was typical of the times that these two former companions and former allies should, as old men, end up fighting each other to the death.