Mr Buffett said he had paid income tax every year since 1944 following Mr Trump's assertion that he had taken a "massive deduction" during Sunday's TV debate with Democrat Hillary Clinton.
In 1995, Mr Trump claimed losses of $916m (Â£736m) to reduce his tax burden.
There is no evidence he did anything illegal.
Mr Trump was asked during the debate by moderator Anderson Cooper if he had taken advantage of the "carryforward" rule, which allows businesspeople to offset a big loss incurred one year against income made in subsequent years for tax purposes.
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"Of course I do. Of course I do, and so do all of her donors, or most of her donors," he said, referring to Mrs Clinton's supporters, before going on to name Mr Bufffett.
Mr Buffett said he had never taken advantage of the carryforward rule, in a statement on Monday.
"I have paid federal income tax every year since 1944, when I was 13. (Though, being a slow starter, I owed only $7 in tax that year.) I have copies of all 72 of my returns and none uses a carryforward," he said.
Mr Buffett said his 2015 federal income tax payment had been $1.8m after calculating gross income of $11.5m from which deductions of $5.5m, including $3.5m of charitable donations, were then subtracted. He also said he had given away a further $2.85bn to charity.
He suggested Mr Trump make his own tax details public, something the Republican candidate has so far refused to do.
"I have no problem in releasing my tax information while under audit. Neither would Mr Trump - at least he would have no legal problem," Mr Buffett said.
Mrs Clinton has released her 2015 tax return, showing that she and her husband Bill paid a 34% rate of federal tax and a 9% rate of state tax on a total income of $10.5m.
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Last updated October 10, 2016
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US investor Warren Buffett has released his tax details after Republican candidate Donald Trump accused him of using loopholes to avoid paying tax.