Ramaphosa emerged the winner in the tightest election for the party leadership ever, beating Nkosazana Dlamini-Zuma, President Jacob Zuma’s former wife and chairperson of the African Union.
The former trade unionist beat Dlamini-Zuma with just 150 votes, winning 2441 votes to his challenger’s 2261 votes.
Observers of South Africa’s politics believe that Ramaphosa’s victory may quicken President Jacob Zuma’s end in office.
Another election for the country’s presidency is not due until 2019.
Zuma backed his wife, who was also a former minister under Nelson Mandela and Thabo Mbeki.
Mr Ramaphosa, a former trade unionist and businessman campaigned on a promise to root out corruption and save the ANC from losing its majority for the first time at the 2019 election.
Also elected are David Mabuza as Deputy President,Gwede Mantashe as chairperson, Ace Magashule as secretary-general, Jessie Duarte as deputy secretary-general and Paul Mashatile as Treasurer-general.
Reuters