Bureau of Prisons spokesman Chris Burke said the artist, whose real name is Clifford Harris, was released at 7:29 a.m. Central time from the Forrest City low-security prison in Arkansas.
The rapper was sentenced to 11 months in prison in October for breaking his federal probation after he was arrested in Los Angeles on drug charges. He had been set for release at the end of September.
His attorney, Jonathan Leonard, confirmed T.I. was released but did not immediately say where his client was going.
He previously served about seven months in the Arkansas prison in 2009 before being released on probation.
Harris was originally arrested in 2007 after trying to buy unregistered guns and silencers from undercover federal agents. That came after Harris' best friend was killed following a post-performance party in Cincinnati in 2006. The rapper has said the bullets that killed his friend were meant for him.