Buffett, 75, plans to commit 10 million class B shares of his company, Berkshire Hathaway, to the Gates Foundation. They will be distributed at a rate of 5 percent of the balance annually. Based on the current value of the stock, Buffett's commitment is more $30 billion, which doubles the size of the funds available to the Gates Foundation.
The Gates Foundation will ultimately receive 85 percent of Buffett's personal wealth, rather than the investor's three children or the foundations that they run.
"My kids were elated when I told them (about the Gates Foundation donation). They knew my views on inherited wealth and shared them," Buffett said during a press conference on Monday. "I believe in equality of opportunity...They should not inherit my position in society, based on the womb that they were born from."
Buffett, a long-time friend of Gates, said he chose to allocate the bulk of his wealth to the Gates Foundation after becoming familiar with the organization and the results it had achieved, based on dollars invested.
"The results are terrific," Buffett said.
The Gates Foundation focuses on global health issues, such as the GAVI Alliance to distribute vaccines to children in poor countries, and education, such as the United Negro College Fund Gates Millennium Scholars Program.
"We've known Warren since 1991, and it is his view that wealth should go back to society that got us thinking of our own foundation," Gates said during the press conference.
While Buffett will serve as a director on the Gates Foundation, he said he prefers spending his time as a professional money manager at Berkshire Hathaway and leaving the details of investing his charitable contributions to others.
When investing, Buffett said he seeks companies that are easy to understand. But the billionaire noted that philanthropy is the opposite. He said it requires a willingness to take large risks to fix complex problems that others have likely failed trying to solve.
The Gates Foundation not only faces that challenge but also the challenge of doubling the level of its funding to charities.
"It'll be a big challenge to make sure we're using the money in the right way," Gates said. "We'll be giving away (a combined) $3 billion a year and will do our best to make sure all the money is well spent."
The Gates Foundation plans to delve deeper in its existing areas of focus, Melinda Gates said during the press conference. It will also possibly expand into other issues, such as microlending in order to help poor regions become more self-sufficient in agriculture and biotech, she said.
She added that despite Buffett's financial commitment, the Gates Foundation will continue to partner with other charitable foundations to maximize financial resources and lessons learned. The Gates Foundation, for example, works with the Michael and Susan Dell Foundation to invest in Texas schools, as well as the David and Lucile Packard Foundation to deliver medicines in India.
Buffett's financial commitment to the Gates Foundation is also contingent upon either Gates or his wife remaining actively involved in the organization. Earlier this month, Gatesfrom his daily involvement with Microsoft as its chief software architect, in order to concentrate on the foundation full-time.
Reuters contributed to this report.