Mr Mandela had suffered from a series of lung infections over the past two years and died at home in the company of his family.
The news of his passing was made in a statement made by South African President Jacob Zuma and was broadcast on national TV.
"Our our nation has lost its greatest son," said Mr Zuma, who praised the Mandela family for sacrificing so much "so that our people could be free."
"Our thoughts are with the South African people who today mourn the loss of the one person who more than any other came to embody their sense of a common nation," he said from Pretoria.
"Our thoughts are with the millions of people across the world who embraced Madiba as their own and who saw his cause as their cause.