Members of the Democratic National Committee will meet in Atlanta, Georgia to select the party's new leader. With seven potential candidates, the contest is thought to be one of the most competitive in decades.
All standing for election are Tom Perez, Keith Ellison, Pete Buttigieg, Sally Boynton Brown, Peter Packarsky, Jehmu Greene and Sam Ronan. Perez, former Labour Secretary, is thought to hold the largest share of the vote among the DNC's 447 members, with Minnesota US Representative Ellison his main challenger.
The candidates represent a diverse group, taking in politicians, lawyers, a television analyst and a US veteran, 27-year-old Ronan. Perez, who is backed by many of former President Obama's administration, is the son of Dominican immigrants. Meanwhile Ellison, who is supported by Senators Elizabeth Warren and Bernie Sanders, was the first Muslim to be elected to Congress.
The process follows the shock defeat of Hilary Clinton by outsider Donald Trump in last year's presidential election. Though Clinton won the popular vote, Trump claimed victory after winning 306 of the 538 electoral colleges, to Clinton's 232.
The party hopes to heal rifts exposed during both the primaries and election campaign, between those seen as the old guard, such as Clinton, and a more progressive faction of the party. Clinton's defeat was seen by many, as with the Brexit vote in Great Britain's referendum on membership of the EU, as a vote against the so-called 'political elite'.
Perez tweeted about the need for unity in the party, ahead of Saturday's vote. He said: "The arc of the moral universe bends towards justice, but it doesn't bend alone.
"As Dems, we must come together to move progress forward."
The election saw the lowest voter turnout in 20 years at 55.4%, compared to 63.7% in 2008 when Barack Obama stood for his first term in office. In a CNN debate this week, Ellison said increasing voter turnout was key to the future success of the party.
He said: "We can actually help Democrats win all over the country so that we can get rid of Donald Trump. That means we focus on turnout, and that is how we succeed."
Exit polls from the 2016 election showed Trump scored particularly highly among the older, white population, while Clinton was by far the favourite among younger and non-white voters. In total, 62% of white men voted for Trump, as did 52% of white women.