Biden is set to take office on Jan. 20.
At a rally in Georgia on Monday, Trump again claimed falsely that he had won the state and declared the Nov. 3 vote "rigged," an assertion that some Republicans have worried will dissuade his supporters from voting on Tuesday.
Both Loeffler and Perdue have strongly backed Trump's challenge to Biden's win. Biden, who held his own rally on Monday in Atlanta, was the first Democratic presidential candidate to win in Georgia since 1992.
In Marrieta, LaVonte Jackson, 42, voted for the Democrats, saying, "Kamala and Biden have a lot of work to do, especially after four years of Trump. I don't know if there's been a more important vote."