"I will miss Lisbon and my family will too. These were some wonderful five years," Aimar told Benfica TV.
The 33-year-old said he wanted to keep playing football but did not say whether he would return to his homeland, where he became an idol as a youngster at River Plate.
"I suppose I will keep playing because I have the will, I feel that need. But I don't know for how longer," he said.
Aimar played over 100 matches for Benfica since arriving from Real Zaragoza in 2008. Nicknamed "El Mago" - the magician - he marshalled the midfield when Benfica last won the league in 2010.
His time at the Lisbon club was plagued by several injuries but, with his slick passing and dribbling, Aimar was always one of the team leaders and put in some memorable performances both in Europe and domestically.
- Sports & Recreation