The man who was jailed by for 27 years by the apartheid regime for his ANC activities before winning South Africa's first democratic election is celebrating his birthday in his home village of Qunu, in southeast South Africa, with his family and 500 guests.
Tributes for Mandela have flowed in from around the world, with tens of thousands of messages already posted on a site set up by admirers, www.happybirthdaymandela.com.
Speaking on Thursday night, South Africa's last apartheid president, FW de Klerk, said: "Nelson Mandela used his personal charm to promote reconciliation and to mould our widely diverse communities into an emerging multicultural nation. This, I believe, will be seen as his greatest legacy."
The South African government issued a birthday message to Mandela, saying: "You have left us a rich legacy from which Government abundantly draws inspiration as it works for reconstruction and development, economic prosperity and national unity."
Since leaving office eight years ago, Mandela has focused his efforts on fighting the spread of AIDS in Africa, in recent years through the 46664 AIDS fundraising campaign, named after his prison number.