Officials said that Mandela, 94, was admitted to a Pretoria hospital on Saturday for routine medical tests and to "manage existing conditions in line with his age."
"The doctors have completed the tests. He is well and as before, his health remains under the management of the medical team," a spokesman for the South African President's office said.
In December, the anti-Apartheid activist was hospitalized for 18 days. He was treated for gallstones and a lung infection.
Despite rare public appearances, Mandela, who is credited with changing race relations in South Africa, remains hugely popular in the country.
In November 2012, banknotes featuring Mandela's image were printed and entered into circulation in South Africa.
After enduring nearly three decades of prison, much of it at hard labor in a lime quarry, Mandela emerged as a gentle leader who was elected South Africa's first black president in 1994.
He was awarded the Nobel Peace Prize for his leadership in ending apartheid without violence, and later became a global statesman who inspired millions people around the world.