Image caption Mr Allen founded Microsoft with Bill Gates in 1975

Microsoft co-founder Paul Allen has said he will commit the majority of his estimated $13.5bn (£8.8bn) fortune to philanthropy after his death.

Mr Allen follows fellow co-founder Bill Gates in pledging billions of dollars to projects designed to help others.

He set up a charitable foundation 20 years ago that has given $400m. He has personally donated a further $600m.

Mr Allen founded technology giant Microsoft with Mr Gates in 1975 but left the company in 1983.

Famous philanthropists Andrew Carnegie , rose from a poor Scottish immigrant to an American steel magnate, retired in 1901 and donated his fortune to found libraries and cultural institutions, including New York's Carnegie Hall

, rose from a poor Scottish immigrant to an American steel magnate, retired in 1901 and donated his fortune to found libraries and cultural institutions, including New York's Carnegie Hall John D Rockefeller , oil magnate who spent the last 40 years of his life donating to medical research and education, died in 1937 aged 97

, oil magnate who spent the last 40 years of his life donating to medical research and education, died in 1937 aged 97 Paul Newman , US actor, created the "Newman's Own" range of foods in 1982 with author A E Hotchner, giving profits to charity

, US actor, created the "Newman's Own" range of foods in 1982 with author A E Hotchner, giving profits to charity Chuck Feeney , Irish-American who earned his fortune in duty free and luxury retail, gave $8bn in 1982 to his foundation Atlantic Partnerships, which invests in health and social projects

, Irish-American who earned his fortune in duty free and luxury retail, gave $8bn in 1982 to his foundation Atlantic Partnerships, which invests in health and social projects George Soros , Hungarian investor famous for the 1992 "Black Wednesday" attack on sterling, set up the Open Society Institute in 1993 to promote freedom and civil society in eastern Europe and elsewhere

, Hungarian investor famous for the 1992 "Black Wednesday" attack on sterling, set up the Open Society Institute in 1993 to promote freedom and civil society in eastern Europe and elsewhere Bill Gates , Paul Allen's partner in Microsoft, set up the Gates Foundation with wife Melinda in 2000, which he now runs full-time, fighting global poverty and disease

, Paul Allen's partner in Microsoft, set up the Gates Foundation with wife Melinda in 2000, which he now runs full-time, fighting global poverty and disease Warren Buffett, American investor known as the "Sage of Omaha", pledged in 2006 to give 99% of his wealth - recently estimated by Forbes at $47bn - to the Gates Foundation and other charities Send us your comments

Charity pledge

"I want to announce that my philanthropic efforts will continue after my lifetime," said Mr Allen, the 37th richest man in the world according to Forbes magazine.

"I've planned for many years now that the majority of my estate will be left to philanthropy to continue the work of the foundation and fund non-profit scientific research."

The announcement comes a month after Mr Gates and fellow billionaire Warren Buffett launched a campaign to urge the richest individuals in the US to pledge half of their fortunes to charity.

Cancer fight

Mr Allen left Microsoft in 1983 after being diagnosed with the blood cancer, Hodgkin's disease.

He successfully beat the illness and went on to become a successful venture capitalist with his media and communications investment firm, Vulcan, from 1986.

In a bitter irony, Mr Allen's sister revealed in 2009 that the entrepreneur had recently developed another form of blood cancer, non-Hodgkin's lymphoma.