President Dilma Rousseff is accused of using accounting tricks to hide large budget deficits.
Rousseff will be suspended and replaced for up to six months by Vice President Michel Temer pending a trial in the Senate.
The trial will determine whether Rousseff can serve out her second term, or whether her ally-turned-enemy, Temer, will remain in the top job through the December 2018 end of the term.
The result represents a victory for the pro-impeachment camp.
It was significantly higher than the simple majority of 41 votes needed to suspend her.
It sends a signal that Rousseff faces an uphill battle to return to power.
Thursday’s vote capped a marathon session in the Senate that lasted more than 20 hours.