The Argentine's previous deal with the Portuguese outfit had been set to expire at the end of the season and the player had been linked with a January move to Uruguayan outfit Nacional.
However, Benfica announced on Thursday evening that the player has signed on for another season at the Estadio da Luz.
"The agreement was reached in less than 10 minutes, since both the player and the President of Benfica [Luis Filipe Vieira] had long expressed the desire to extend the bond that united them," read a statement on the club's official website.
"Pablo is an example to follow," commented team-mate Ezequiel Garay on Aimar's extension.
Aimar signed from Zaragoza in 2008 and has now racked up over 140 appearances for Benfica.
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