It brings Iraq one step closer to forming a new government in Iraq after weeks of political tensions following last month's parliamentary election.
Sadr's Sairoon Alliance won 54 seats in the May vote to become the largest bloc in Iraq's 329-seat parliament, while Abadi's alliance - once seen as a frontrunner - came in third, with just 42 seats.
The electoral commission of Iraq announced that 44.5 percent of those eligible had cast their ballots in national elections.
Over 7,000 candidates contested the 329 seats in the parliament that will determine a new president, a new prime minister and a new government in Iraq.
This is the fourth such poll since the 2003 US invasion of the country, that led to a sharp rise in sectarian tensions, violence, and acts of terrorism.
Analysts say the next prime minster will face huge challenges, such as rebuilding a country shattered by years of war against foreign-backed Daesh terrorists , as well as years of occupation by US military forces.
Western-created and Western-trained Daesh terrorists unleashed a campaign of death and destruction in Iraq in 2014, overrunning vast swathes in lightning attacks. Iraqi army soldiers and allied fighters then launched operations to eliminate the terrorist group, and reclaim lost territory.
