His western campaign had taken a heavy toll on his army as well as his treasury.
Despite (or perhaps because of) this, Pyrrhus went to war yet again.
The realm of his rival king Antigonus Gonatas of Macedon was the most obvious target.
Pyrrhus raised an army from his Epirote garrisons, Gallic mercenaries and the troops he had brought back from Italy and marched east into Macedon.
He won an easy victory at the Battle of the Aous and took most of Macedon.

Antigonus managed to hold on to a number of coastal cities.
He then waited for an opportunity to reclaim his kingdom while Pyrrhus was already looking for another war to fight.
Furthermore Pyrrhus made himself very unpopular in Macedon by allowing his Gauls to plunder the tombs of the Macedonian kings at Aegae.

In 272 BC, Cleonymus, a Spartan of royal blood who was hated among fellow Spartans, asked Pyrrhus to attack Sparta and place him in power.
Pyrrhus agreed to the plan, intending to win control of the Peloponnese for himself, but unexpected strong resistance thwarted his assault on Sparta.
On the retreat he lost his firstborn son Ptolemy, who had been in command of the rearguard.

Pyrrhus had little time to mourn, as he was immediately offered an opportunity to intervene in a civic dispute in Argos.
Since Antigonus Gonatas was approaching too, he hastened to enter the city with his army by stealth, only to find the place crowded with hostile troops.
During the confused Battle of Argos in the narrow city streets, Pyrrhus was trapped.
 While he was fighting an Argive soldier, the soldier's old mother, who was watching from a rooftop, threw a tile which knocked him from his horse and broke part of his spine, paralyzing him.
 Whether he was alive or not after the blow is unknown, but his death was assured when a Macedonian soldier named Zopyrus, though frightened by the look on the face of the unconscious king, hesitantly and ineptly beheaded his motionless body.
This story is later recounted by Plutarch in his Life of Pyrrhus.

Antigonus had him cremated with all honours and sent his surviving son Helenus back to Epirus.
That same year, upon hearing the news of Pyrrhus's death, the Tarentinians surrendered to Rome.
His western campaign had taken a heavy toll on his army as well as his treasury. Despite (or perhaps because of) this, Pyrrhus went to war yet again. The realm of his rival king Antigonus Gonatas of Macedon was the most obvious target. Pyrrhus raised an army from his Epirote garrisons, Gallic mercenaries and the troops he had brought back from Italy and marched east into Macedon. He won an easy victory at the Battle of the Aous and took most of Macedon.
Antigonus managed to hold on to a number of coastal cities. He then waited for an opportunity to reclaim his kingdom while Pyrrhus was already looking for another war to fight. Furthermore Pyrrhus made himself very unpopular in Macedon by allowing his Gauls to plunder the tombs of the Macedonian kings at Aegae. 
In 272 BC, Cleonymus, a Spartan of royal blood who was hated among fellow Spartans, asked Pyrrhus to attack Sparta and place him in power. Pyrrhus agreed to the plan, intending to win control of the Peloponnese for himself, but unexpected strong resistance thwarted his assault on Sparta. On the retreat he lost his firstborn son Ptolemy, who had been in command of the rearguard.
Pyrrhus had little time to mourn, as he was immediately offered an opportunity to intervene in a civic dispute in Argos. Since Antigonus Gonatas was approaching too, he hastened to enter the city with his army by stealth, only to find the place crowded with hostile troops. During the confused Battle of Argos in the narrow city streets, Pyrrhus was trapped.  While he was fighting an Argive soldier, the soldier's old mother, who was watching from a rooftop, threw a tile which knocked him from his horse and broke part of his spine, paralyzing him.  Whether he was alive or not after the blow is unknown, but his death was assured when a Macedonian soldier named Zopyrus, though frightened by the look on the face of the unconscious king, hesitantly and ineptly beheaded his motionless body. This story is later recounted by Plutarch in his Life of Pyrrhus. 
Antigonus had him cremated with all honours and sent his surviving son Helenus back to Epirus. That same year, upon hearing the news of Pyrrhus's death, the Tarentinians surrendered to Rome.
Pyrrhus of Epirus