The trail was set after some allegations that she illegally manipulated the government’s budget to hide a growing fiscal deficit.
“Today we are trying to overcome this situation by removing an irresponsible government. We have no alternative,” said Senator Blairo Maggi, as cited by Reuters.
The Senate on Thursday voted 55 to 22 in favor of opening the trial.
Vice-President Michel Temer will now assume the presidency while Ms Rousseff’s trial takes place.
The impeachment process against Rousseff started back in 2015. The charges against the first female president of Brazil include administrative misconduct, disregarding the federal budget, and corruption.
Tensions were plain to see outside Congress, where police erected a giant metal fence to keep apart small rival groups of demonstrators.
Rousseff has condemned the impeachment drive as a coup, pledging to fight on during the trial.