The Argentina international has officially extended his contract until June 2018 and is determined to help the club to great success after "difficult moments" last season
The Argentina international reached an agreement earlier this month on an improved deal which will run until June 2018 and include a €100 million buyout clause.
Following a spell of uncertainty over his future, in which the former Liverpool player was linked with a move to Napoli, Mascherano says he is now eager to achieve greatness at Camp Nou once again following a tough end to the 2013-14 campaign.
"I am very happy to continue at this great club and to share the dressing room with great players," he told the club's official website after officially putting pen to paper on his new agreement.
"The dream for this season is that everything goes well. We have renewed ambitions after having spent a season with difficult moments.
"The idea is to be committed to the club until the end of the contract. Hopefully I can live up to the institution."
Mascherano has spent four years with Barcelona since arriving from Anfield for €22m in August 2010.