Paul Washer is in "critical condition" after suffering a heart attack on Monday night, according to supporters.
An update to his official Facebook page after the heart attack said that although he was in critical condition, he was "stable."
"Please pray for him and his family!" the message read.
A later update said there was "lots of good news" after Washer underwent tests, and that he would be released from hospital soon.
"Everything looks good! He's looking forward to being home in a few days," the post said.
Organizers of the G3 Conference, where Washer is due to speak in 2018, tweeted that the 55-year-old had suffered the heart attack at his home in Virginia.
"He is stable and under the care of doctors. Pray," the conference organizers said.
Washer is the founder of HeartCry Missionary Society, and is also a popular preacher and conference speaker.
Washer set up HeartCry in Peru in 1988 with the aim of supporting indigenous missionaries in reaching their own people with the Gospel and establishing churches. It has since grown far beyond Latin America to have operations in Africa, Asia, Eurosia, Europe and the Middle East.
Some 238 missionary families are supported by the missionary agency in 41 countries around the world.
Washer is conservative in his theology and attracted attention in 2002 when he preached a no holds barred sermon to around 5,000 young people, called the 'Shocking Youth Message', in which he said that many of them could end up in Hell, even those who professed to be believers in Jesus.
A video of the sermon on YouTube has had nearly two million views. In the sermon, he strongly criticized American Christianity, saying it was "more based on a godless culture than it is upon the Word of God," and was deceiving people into believing that they were going to Heaven because they had said one prayer in their life.
"I'm not troubled in my heart about your self-esteem. I'm not troubled in my heart about whether or not you feel good about yourself, whether or not life is turning out like you want it to turn out, or whether or not your checkbook is balanced. There's only one thing that gave me a sleepless night. There's only one thing that troubled me all throughout the morning, and this is this. Within a hundred years, a great majority of people in this building will possibly be in Hell. And many who even profess Jesus Christ as Lord will spend an eternity in Hell," he said.
Washer's Facebook page has been inundated with messages of support and prayer since news spread of his condition spread.
"OOOOH Lord God Almighty...save Brother Paul, surely his work here on earth cannot be done....heal his heart completely, as if NO heart attack has taken place...LORD glorify Yourself through this testimony, in JESUS Holy name I ask this of You. Amen!" read one Facebook post.
Another said: "Prayers today for dear Paul and his family. I only heard today. Such a very sincere and earnest teacher. God bless, support and comfort him and his wife and children at this time."
Washer is married to Charo and they have three children, Ian, Evan and Rowan.
