Mandela, affectionately known as Madiba by South Africans, died in December after a long illness.
He was imprisoned for 28 years for supporting the end of apartheid -- or racial segregation -- in South Africa, and was released in 1990.
Tutu was a close friend of Mandela's while he was in prison.
“I didn't think there would be a disillusionment so soon,” Tutu said of South Africa since the end of apartheid. “I'm glad that Madiba is dead. I'm glad that most of these people are no longer alive to see this."