SÃO PAULO—Brazil’s Chamber of Deputies is voting Sunday on whether or not to send the impeachment process against President Dilma Rousseff to the Senate for trial.

The most recent tally was 308 in favor of impeachment and 107 against or abstaining after more than four hours of voting, a result that prompted an official of Ms. Rousseff’s Workers’ Party to concede that the government had lost the vote.

“The...