"The corona disease has been eliminated thanks to God," Mr Magufuli told worshippers in a church in the capital, Dodoma.
The World Health Organization (WHO) has expressed concern over the government's strategy on Covid-19.
The government has stopped publishing data on the number of coronavirus cases in the country.
On 29 April, the last day official data was released, there were 509 cases, with 21 deaths in Tanzania. However, Mr Magufuli said last week that only four patients were receiving treatment in the largest city, Dar es Salaam.
Last month, Tanzania's government dismissed a US embassy warning that hospitals in Dar es Salaam were "overwhelmed" and that the chances of contracting the virus was "extremely high".
Mr Magufuli has repeatedly said the health crisis has been exaggerated and urged people to attend services in churches and mosques, saying that prayers "can vanquish" the virus.
What did Magufuli say?
"I want to thank Tanzanians of all faiths. We have been praying and fasting for God to save us from the pandemic that has afflicted our country and the world. But God has answered us.
"I believe, and I'm certain that many Tanzanians believe, that the corona disease has been eliminated by God," he told worshippers on Sunday in Dodoma.
His remarks were welcomed with applause and celebratory ululation.
Mr Magufuli also commended the priest and worshippers for not wearing gloves and masks to protect themselves from the virus.
SOURCE: BBC