The US has the highest number of billionaires, with 415, including 55 who were new to the list. Germany, which has long held the runner-up spot, was second again. Russian gains
Russia climbed to number three in the country rankings with 53 billionaires, two less than Germany, but the total worth of the Russians surpassed the Germans, at $282bn compared to $245bn, Forbes said.
The average age of Russia's billionaires was 46.
1. Bill Gates - co-founder of Microsoft - $56bn
2. Warren Buffett - investor and businessman - $52bn
3. Carlos Slim Helu - telecoms investor - $49bn
4. Ingvar Kamprad and family - Ikea founder - $33bn
5. Lakshmi Mittal - steel magnate - $32bn
6. Sheldon Adelson - casino developer - $26.5bn
7. Bernard Arnault - CEO of luxury goods holding company - $26bn
8. Amancio Ortega - Zara clothes chain founder - $24bn
9. Li Ka-shing - investor - $23bn
10. David Thomson and family - inheritance - $22bn
In Asia, India had the highest number of billionaires, overtaking Japan, which had held the top spot for two decades.
India's 36 billionaires are worth a total $191bn.
Bill Gates, chairman of computer software company Microsoft, was the world's richest man for the 13th straight year, with a $56bn fortune.
Warren Buffett, chief executive of Berkshire Hathaway Inc, was second and Carlos Slim Helu, a Mexican telecoms tycoon, remained third.
In China, Yan Cheung, chairwoman of Nine Dragons Paper, made history as China's richest person and was one of three self-made women born in the communist country to find their way onto the list this year.
She is worth $2.4bn and is 390th on the list. 'Notable advance'
"This is the richest year ever in human history," Steve Forbes, Chief Executive of Forbes, said. "Never in history has there been such a notable advance."
The heirs to the Wal-Mart Stores fortune were pushed out of the top 20 this year as their company's stock languished, along with Michael Dell, founder of computer maker Dell Inc.
Yoshiaki Tsutsumi, the once-powerful Japanese industrialist who was briefly the world's richest person in 1987, has dropped off the billionaires list, the magazine said.
The former chairman of Kokudo Corp, the core firm of regional railway operator Seibu Railway group, received a suspended prison sentence in October 2005 for falsifying financial statements and insider trading.