Rousseff is accused of breaking the law by juggling government accounts to disguise the depth of budget shortfalls during her 2014 reelection.
She argues that this relatively technical accusation is not an impeachable offense.
Momentum for her removal however is being fueled by a massive recession, political paralysis and a sprawling corruption scandal that have reduced approval ratings for Rousseff's government to around 10 percent.
The special commission in the lower house of Congress includes 65 lawmakers from all political stripes. Their meeting dragged on for hours because lawmakers who were not part of the group but who signed up earlier were allowed to speak.
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By the time the session ended at 4:30 am (0730 GMT) 61 lawmakers had spoken, 40 of whom favor removing Rousseff and 20 who oppose the move. One lawmaker claimed to be "undecided."
The commission resumes work on Monday, with a vote on whether they recommend impeachment scheduled for 5 pm (2000 GMT).
If approved, the full lower chamber on Friday will begin debate on whether the impeachment request should move on to the senate, which will then have the final word on removing the president.