Brazilian president Dilma Rousseff has condemned as a "coup" the Senate's decision to impeach her.
Senators voted to suspend her by 55 votes to 22 after an all-night session that lasted more than 20 hours.
Ms Rousseff is accused of illegally manipulating finances to hide a growing public deficit ahead of her re-election in 2014, which she denies.
Addressing the nation from the presidential palace, Ms Rousseff vowed to fight the "injustice" by all legal means.
In her TV speech Mr Rousseff said that she may have made mistakes but had committed no crimes, adding: "I did not violate budgetary laws."
She said: "What is at stake is respect for the ballot box, the sovereign will of the Brazilian people and the constitution."
Vice-President Michel Temer will now assume the presidency while Ms Rousseff's trial takes place.
The trial may last up to 180 days, which would mean Ms Rousseff would be suspended during the Olympic Games in Rio de Janeiro, which start on 5 August.
Ms Rousseff made a last-ditch appeal to the Supreme Court to stop proceedings, but the move was rejected. Her suspension brings an end to 13 years of the rule of her Workers' Party.
In a speech at the end of the all-night Senate session, attorney general Jose Eduardo Cardozo said the impeachment request did not have legal basis and that the opposition wanted to remove a democratically-elected president.
He said senators were condemning an "innocent woman" and that impeachment was a "historic injustice".
Why did senators seek impeachment?
All 71 senators present for the vote made their case for or against impeachment in 15-minute slots. They finished at 5.45am local time, more than 20 hours after the session opened.
In the Senate, the arguments given for the trial were mainly economic.
Many blamed President Rousseff, for the dire straits the country's economy is in.
Brazil is suffering from its worst recession in 10 years, unemployment reached nine percent in 2015 and inflation is at a 12 year high.
Ms Rousseff was first sworn into office in January 2011 and started a second term in 2015.
Senator Aecio Neves, who lost to Ms Rousseff in the 2014 presidential election, said: "Populist governments always act with fiscal irresponsibility and when they fail they appeal to the old 'us vs them' argument."
"The poorest and most vulnerable in society, who need the government support the most, always end up paying the bill," he added.
Mr Neves said he was voting for an impeachment trial.
Ataides Oliveira of the opposition PSDB party said that "today, we're going to retrieve the country from the hands of the PT (Ms Rousseff's Workers' Party) and give it back to the Brazilian people".
Former football player turned senator Romario said Brazil was in "a very serious crisis" before revealing that "after much thought" he had decided to back her impeachment trial.
What did Dilma Rousseff's backers say?
Those arguing against the impeachment trial repeated her comments that it was tantamount to a coup d'etat.
Senator Telmario Mota said that "today we are seeing an attempted takeover of power which calls itself impeachment".
He added that the impeachment proceedings were "born of revenge, hatred and revenge".
Senator Fatima Bezerra from the Workers' Party called the proceedings "a farce".
"Those who back this coup d'etat won't ever be forgiven," she warned.
The 180 days allocated for the trial to take place expire on 8 November.