After a long wait, he is now poised to lead a party and nation that have both been deeply tarnished by the eight-year rule of President Jacob Zuma.
The party's Chief Whip Jackson Mthembu announced on Twitter that he voted for Ramaphosa, while police minister Fikile Mbalula tweeted that he had cast his vote for Dlamini-Zuma.
He said Zuma would be "most welcome" in the league after he steps down as president.
Outgoing President Jacob Zuma's second and final term as party leader has ended after a scandal-ridden tenure that has seen a plummet in the popularity of Nelson Mandela's liberation movement.
Speaking after a walkabout at the Nasrec Expo Centre, in Johannesburg, where the ANC is holding its 54th national conference, Zuma said that he was happy with the conduct of the delegates at the conference and how the event was proceeding.
Pension reforms too late for middle-aged, says Sir Steve Webb
Combined these two changes will cost the Treasury £600 million in tax relief in 2020/21, a DWP analysis paper said. Now employers must match the contribution of workers who put a penny of every pound they earn into a pension fund.
The slight favourite, as of Sunday night, was Deputy President Cyril Ramaphosa, who has vowed to fight corruption and introduce pragmatic reforms to create jobs and restore growth in a stagnant economy.
For one, delegates are not bound by their branches when they vote at the conference.
Voters are frustrated with the ANC as Zuma's administration has been mired in scandal and corruption allegations. ANC deputy president Cyril Ramaphosa and ANC MP Nkosazana Dlamini-Zuma are contesting to succeed Zuma as the 13th ANC president.
"Anyone who wins we are going to support and rally behind", said Sasekani Manzini, a spokeswoman for the ANC in Mpumalanga province.Polls suggest that she is supported by only about 16 per cent to 20 per cent of South Africans, while Mr. Ramaphosa is supported by more than 42 per cent. "Even if there is a strong lead in terms of branch nominations by the Ramaphosa camp, it's not clear-cut".
After a series of court judgments against him, including rulings that ordered prosecutors to pursue corruption charges against him, Mr. Zuma complained on Saturday that the rulings were "dangerous" and made it "difficult to govern".