Former Brazilian leader Luiz Inacio Lula da Silva has vowed to appeal after being convicted on corruption charges and sentenced to nearly 10 years in prison.
The ruling marked a stunning fall for Lula, one of the country's most popular politicians, and a serious blow to his chances of a political comeback.
The former union leader, who won global praise for policies to reduce stinging inequality in Brazil, faces four more corruption trials and will remain free on appeal.
The verdict on Wednesday is the highest-profile conviction yet in a corruption investigation that has revealed a sprawling system of graft at the highest levels of Brazilian business and government.
Judge Sergio Moro found Lula, 71, guilty of accepting 3.7 million reais ($A1.6 million) worth of bribes from engineering firm OAS SA.
The amount is what prosecutors say the company spent refurbishing a beach apartment for Lula in return for help winning contracts with state oil company Petroleo Brasileiro.
Federal prosecutors have accused Lula, Brazil's first working-class president from 2003 to 2011, of masterminding a corruption scheme that was uncovered in a probe into kickbacks around Petrobras.
Lula's legal team says he is innocent and they will appeal.
"For over three years, Lula has been subject to a politically motivated investigation," they said in a statement.
"No credible evidence of guilt has been produced and overwhelming proof of his innocence blatantly ignored."
Lula would be barred from office if the verdict is upheld by an appeals court, which is expected to take at least eight months to rule.
Lula's two terms were marked by a commodity boom that momentarily made Brazil one of the world's fastest-growing economies.
Upon leaving office and getting his hand-selected successor, Dilma Rousseff, elected, Brazil's economy soured.
The nation is only now beginning to emerge from its worst-ever recession.
Rousseff was impeached last year for breaking budgetary rules.
She and her backers say her ouster was actually a "coup" orchestrated by her vice-president and now-President Michel Temer, who himself faces corruption charges.