PATRICE Motsepe, a mining billionaire, and his family, are giving half the funds generated from assets owned by the family to the Motsepe Family Foundation.
The funds will be used to uplift those less well off, the family said in a statement.
"I decided quite some time ago to give at least half the funds generated by our family assets to uplift poor and other disadvantaged and marginalised South Africans but was also duty-bound and committed to ensuring that it would be done in a way that protects the interests and retains the confidence of our shareholders and investors," Mr Motsepe said in a statement.
Mr Motsepe founded African Rainbow Minerals (ARM), which he chairs. He is also chairman of Harmony Gold, in which ARM is a shareholder.
Mr Motsepe also announced on Wednesday that he had joined the Giving Pledge, launched by Microsoft founder Bill Gates and investor Warren Buffett in June 2010.
Mr Gates, his wife, Melinda, and Mr Buffett have asked US billionaires to give away at least half their wealth during their lifetime or after their death, and to publicly state their intention with a letter explaining their decision.
The Giving Pledge does not accept money or tell people how to donate their money but asks billionaires to make a moral commitment to give their fortunes to charity.
Mr Buffett pledged in 2006 to give away 99% of his wealth to the Bill & Melinda Gates Foundation and family charities. Bill and Melinda Gates have so far donated more than $28bn of their fortune to their foundation.
The full list of billionaires and their letters can be seen at Thegivingpledge.org.