President Donald Trump has endorsed Moore, whose campaign has been clouded by allegations of sexual misconduct toward teenagers.
Moore, 70, a former Alabama Supreme Court chief justice, is battling Democrat Doug Jones, 63, a former U.S. attorney who is hoping to pull off an upset victory in the deeply conservative Southern state.
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Trump backs Alabama Senate candidate Moore
In his final plea to Alabama voters, Roy Moore cast himself as the victim unjust allegations.
Facing voters at last after the year's most bitter US campaign, Alabama Republican Roy Moore cast himself as the victim of a national barrage of unjust allegations of sexual misconduct with teenagers.
Rival Jones, hoping to become the state's first Democratic senator in two decades, declared their race was Alabama's referendum on "who we are and what we're going to tell our daughters."
Allegations aside, President Donald Trump said in a robocall to Alabama voters that he badly needs Moore's own vote in the US Senate.
Former President Barack Obama and his vice president, Joe Biden, also recorded calls for Jones seeking to break the GOP's lock on statewide office in Alabama.
Whether the calls would sway anyone so late in such a highly publicised campaign was an open question. So was the impact of a rash of false news stories that have appeared on social media spreading misinformation.
One website wrongly claimed that one of the women who have accused Moore of sexual misconduct had recanted. Meanwhile, Moore's detractors took to social media to claim he had written in a 2011 textbook that women shouldn't hold elected office. He didn't.
On election eve, Moore called in to a conservative talk radio show in Alabama to lament the tone of the campaign and portray cast himself as the victim of the sexual misconduct allegations.
"We've seen things happen in this campaign that I can't believe to this day," said Moore, who has denied all wrongdoing in contacts with the women who said he behaved inappropriately when they were in their teens and he was a local prosecutor in his 30s. One said he initiated sexual contact when she was 14.
"It's just been hard, a hard campaign," said Moore, a former Alabama Supreme Court chief justice who was twice removed from that post for violating judicial ethics.
At an evening rally in the state's rural southeast, Moore told voters, "If you don't believe in my character, don't vote for me."
Former White House strategist Steve Bannon, who also spoke the Moore rally, argued that the election is "greater than Judge Moore and even greater than the people of Alabama," casting it as a referendum on Trump's agenda.
Alabama has been a solidly Republican state for years, and Moore said he is much more in tune with the issues that matter to voters - and to the president.
