"Cryptocurrencies basically have no value and they don't produce anything," he told CNBC's Becky Quick in a "Squawk Box" interview. "In terms of value: zero."
"I don't have any cryptocurrency and I never will," added Buffett, who was interviewed two days after he released his annual shareholder letter.
Buffett has been a long-time critic of the world's largest digital coin. He called bitcoin "probably rat poison squared," ahead of the 2018 Berkshire Hathaway annual shareholder meeting. A "mirage," "not a currency," and "tulips" are among the descriptors Buffett has used for bitcoin, according to CNBC's Warren Buffett Archive.
Berkshire Vice Chairman Charlie Munger has called it a "turd," and said that trading cryptocurrencies is "just dementia."
Last year, in an attempt to change Buffett's mind, Justin Sun, founder of cryptocurrency TRON and CEO of file-sharing company BitTorrent, bid $4.57 million in a charity auction to have a meal with the bitcoin skeptic.
"When Justin and four friends came, they behaved perfectly and we had a very friendly 3½-hour dinner and the whole thing was a very friendly exchange of ideas," Buffett said. He added that neither he nor Sun changed their stance on bitcoin.