"I will fight, like I have always done in my life. ... I am sure that we will have the opportunity to defend ourselves in the Senate," she told reporters.
But Rousseff slammed the impeachment process against her as unjust, comparing it to a coup.
"Today, above all, I feel injustice," she said.
Rousseff, who became Brazil's first female President when she was elected in 2010, isn't on trial yet. But she could be soon.
The impeachment motion will next go to the country's Senate. If a majority approves it there, Rousseff will have to step down for 180 days
to defend herself in an impeachment trial.
That means Rousseff could be suspended as early as May. That would be about three months before the Summer Olympics kick off in Rio de Janeiro, an event that was supposed to showcase Brazil as a rising power on the global stage.
'I was treated like no one else'
Rousseff is accused of breaking budgetary laws by borrowing from state banks to cover a shortfall in Brazil's deficit and pay for popular social programs.
She told reporters Monday that other leaders have done the same thing.
"The acts that they accuse me of, they were practiced by other presidents of the republic before me. And it wasn't characterized as being illegal acts or criminal acts. They were considered legal," she said. "Therefore, when I feel injustice, it's because, with me, I was treated like no one else was treated."
An analysis by the Folha de Sao Paulo newspaper
, citing figures from the country's central bank, alleges that Rousseff took the practice much further than her predecessors.
Rousseff stressed Monday that she hadn't enriched herself in the process, noting that some of her accusers themselves have been accused of hiding money in foreign bank accounts.
Timing is key
Rousseff's comments Monday echo early remarks she's made about her possible impeachment. But the timing is key.
They were her first public statements since Sunday's contentious vote. And they were another sign that she has no plan to back down.
Rousseff, who was tortured during her country's military dictatorship
, said the impeachment process was similarly unjust. And she said she would draw upon the same strength that helped her in the past to face her critics now.
"In a certain way, I am having my dreams tortured now," she said. "Now, they will not kill the hope in me. Because I know that democracy is always the right way."