Keita ends Barça contract early
The midfielder had one year left on his contract but has activated a clause that allows him to leave should he not start more than half of Barça's fixtures in the previous season.
A statement on the club's website read: "Seydou Keita has announced this evening that he won't be staying at the club next season. FC Barcelona thanks Seydou for his services to the club over the years and wish him professional and personal success in the future."
Keita was one of Pep Guardiola's first signings when he took charge in 2008 and made an immediate impact with six goals as Barça became the first Spanish side to win the treble of La Liga, Copa del Rey and UEFA Champions League.
He continued to be an important player in the following two campaigns as Barça retained the league title and won the Champions League again in 2011, but a mixture of poor form, fitness problems and his participation in the CAF Africa Cup of Nations meant he only started 14 games in La Liga last term.
His last match in a Barcelona shirt came as a late substitute in the Copa del Rey final win over Athletic Bilbao in May, which took his tally of trophies to 14 during his four years at the club.