The Braves (52-43), who are tied for first place in the NL East with the Washington Nationals, announced Uggla's release on their official Twitter account.
Uggla had filled a reserve role after losing his starting job to rookie Tommy La Stella at the end of May.
Last weekend, he showed his frustration by arriving just shortly before the start of a game at Wrigley Field and was suspended by the club for Sunday's game.
The power-hitting Uggla, who originally played for the Marlins and had five successive seasons with 30-plus home runs, batted .179 and struck out 171 times last season.
This season, Uggla was struggling with a .162 batting average and two home runs and 10 RBIs in 48 games.
Atlanta acquired Uggla in November 2010 in a trade with Miami and signed him to a $62 million, five-year contract. He is owed $13 million for 2015.
(Reporting by Larry Fine in Winchester, Kentucky; Editing by Gene Cherry)