Using a walking stick and smiling, Tutu came out of his home in Cape Town's Milnerton area with voting officials and waved to the press who had gathered. He did not speak but blew a kiss to the press.
Tutu won the Nobel Peace Prize in 1984 for his work crusading against South Africa's brutal apartheid system of racial discrimination.
The upcoming elections take place 25 years after the end of apartheid and are the country's sixth all-race polls.
Other elderly people are casting their ballots across South Africa in early voting Monday and Tuesday. Mmaphuti Mabitsela, who is registered as 108 years old, voted at her home in Atteridgeville, near Pretoria, on Monday.