Vice-President Michel Temer will assume the presidency while she is away.
The vote begins an impeachment trial against her which could drag for more than 180 days.
Vice-President Michel Temer will assume the presidency while she is serving her suspension.
She has been accused of manipulating finances to hide growth deficit ahead of her re-election in 2014. She has however denied it.
A last minute attempt to quash the Senate vote on her was rejected by the Supreme Court, paving the way for the vote today.
“We could no longer ignore these crimes and thus voted for impeachment,” Senator Álvaro Dias said.
“Having been assaulted by incompetence and wrongdoing, Brazilians expect punishment.”
'Historic injustice' and a 'farce'
Attorney general Jose Eduardo Cardozo described the impeachment procedure as lacking a legal basis that the opposition wanted to remove a democratically-elected president.
He said lawmakers were condemning an "innocent woman" and that impeachment was a "historic injustice," the BBC reported.
"Those who back this coup d'etat won't ever be forgiven," she added.
Outside Congress, where a metal fence was erected to keep apart rival protests, about 6,000 backers of impeachment chanted "Out with Dilma", while police used pepper spray to disperse gangs of Rousseff supporters, who hurled flares back. One person was arrested for inciting violence, Aljazeera reported.
Ms. Rousseff, 68, is the second Brazilian president to face impeachment since democracy was re-established in the mid-1980s after a long dictatorship. In 1992, Fernando Collor de Mello resigned before the Senate could try him on charges of corruption, according to the New York Times.
She was first sworn into office in 2011 and won a second term bid in 2014.