The 59-year-old Barbosa is Brazil's first black Supreme Court justice. He said today he will retire in late June.
Barbosa's two-year tenure as Supreme Court president was due to expire in November of this year. The court's judges must retire by age 70.
He became the only black ever to serve on the court when he joined it in 2003, even though more than half of the country's 192 million people identify themselves as having African descent.
Over time he gained national and international renown presiding over a high-profile corruption trial involving a congressional cash-for-votes scheme.