The versatile Argentinian has signed a new contract with the Catalan club that will keep him there until June 2019.
A deal had been agreed in principle in July, but the Argentinian has only just wrapped up the new deal now.
Mascherano had been linked with a move away from the Camp Nou, but has put all transfer speculation to bed by signing a new deal.
The 32-year-old joined from Liverpool in 2010, making 289 appearances and winning 17 trophies.
[CONTRACT NEWS] @Mascherano signs his extension to keep him at the Club until 2019. More info at https://t.co/5YQHLmhIlK pic.twitter.com/SXSpFv0dwI
— FC Barcelona (@FCBarcelona) October 17, 2016