"Mr Mandela's renowned political life will forever remain a beacon of excellence," Mugabe, Africa's oldest ruler at 89, said in his first official reaction, carried by the state-run newspaper The Herald.
Mandela, the founding father of modern South Africa and its first black leader, died late Thursday aged 95.
"Not only was he a great champion of the emancipation of the oppressed, but he was also a humble and compassionate leader who showed selfless dedication to the service of his people," Mugabe said.
In a documentary in May, Mugabe said Mandela went "a bit too far in doing good to the non-black communities, really in some cases at the expense of (blacks)."
"That's being too saintly, too good, too much of a saint," he said.
Mandela's death evoked an outpouring of grief and tributes from world leaders and admirers across the globe.
In Zimbabwe, state and private radio stations played music in honour of the anti-apartheid hero while listeners phoned in with condolence messages.
