The vote brought to a boil months of rancorous debate that has seen Dilma Rousseff's ruling coalition collapse and prompted huge street demonstrations.
Brazilian President Dilma Rousseff was on the verge of defeat on Sunday in her attempt to stave off a vote authorizing the Senate to start an impeachment trial, plunging the deeply divided country into crisis.
After four hours of voting the opposition in the lower house of Congress in Brasilia had reached 312 votes -- near its target of 342, or a two-thirds majority, which would send Rousseff to the Senate for the next stage of the process.
A senior leader of her Workers' Party said defeat was inevitable.
"The coup plotters have won here in the house," said Jose Guimaraes, leader of the Workers' Party in the lower house of Congress.
"President Dilma (Rousseff's) government recognizes this temporary defeat but that does not mean that the war is over," Guimaraes said. "The fight will continue in the streets and in the Senate."
The vote brought to a boil months of rancorous debate that has seen Rousseff's ruling coalition collapse and prompted huge street demonstrations.
The chamber's 513 deputies rose one by one to announce their vote at a microphone, greeted by cheers and sometimes jeering from the rest of the chamber.
Earlier, there were hours of debate regularly interrupted by chaotic scenes of deputies leading allies in patriotic anthems or singing parodies about the leftist Rousseff. Others chanted, waved large flags and one deputy even fired off a confetti cannon.
Brazil's first female president is accused of illegal government accounting tricks but, more broadly, is blamed for the country's worst recession in decades and galloping corruption.
The whole procedure was being aired live on television to the country of 204 million, the biggest in Latin America, and also on screens erected in city squares.
Protests Peaceful So FarIn Brasilia, about 53,000 pro-impeachment demonstrators massed outside Congress, according to a police count. About 26,000 turned out on the pro-Rousseff side, separated by a metal fence.
In Rio de Janeiro, which is scrambling to organize the Olympics this August, about 3,000 people each from the two sides demonstrated at separate time slots next to Copacabana beach.
So far, the atmosphere on the streets was peaceful, even festive, with a funk band singing in Rio and protesters blowing trumpets and vuvuzelas, as if at a football game, in Brasilia.
In Sao Paulo, the financial center, thousands of pro-impeachment supporters thronged the central Paulista Avenue, many of them in the country's green and yellow national football shirts.
In Brasilia, psychologist Eric Gamaliel, 29, said he had joined pro-Rousseff protesters because impeachment would mean "Brazil loses a lot. The world will lose a lot. It will be a step backwards."
But farmer Silmar Borazio, 50, who made a 20-hour journey to the capital with pro-impeachment supporters, said Brazil needs change.
"The first thing that needs to happen is for Dilma to leave. We are tired of producing revenue and seeing that in the end nothing improves in the country and it gets stolen," he said.
Senate Could Vote In MayRousseff, 68, is accused of illegal accounting maneuvers to mask government shortfalls during her 2014 reelection. Many Brazilians also hold her responsible for the economic mess and a massive corruption scandal centered on state oil company Petrobras, a toxic record that has left her government with 10 per cent approval ratings.
The president and her allies lobbied frantically in a last-minute effort to turn the tide in Congress. Her mentor, the fiery ex-president Luiz Inacio Lula da Silva, flew back from his home in Sao Paulo to join the final assault.
If impeachment is authorized on Sunday, the Senate would vote, probably in May, on whether to open a trial. In case of a yes vote there, which experts consider likely, Rousseff would step down for 180 days.
During this period she would be replaced by her vice president Michel Temer, who has emerged as a leader of the impeachment drive. If the Senate then ended the trial with a two-thirds majority in favor of ejecting her, Rousseff would have to leave and Temer would stay on until elections in 2018.
Sylvio Costa, who heads the specialist politics website Congresso en Foco, told AFP that Rousseff was nearly sure to go, but that more trouble lies ahead.
"Whoever loses will keep protesting in the streets," he said.
"What's certain is that the crisis will not end today."