Gates regained the No.1 spot after four years increasing his net worth from $67 billion in 2013 to $76 billion. Telecom mogul Carlos Slim Helu had to settle with the second spot, amassing a net worth of $72 billion, down a $1 billion from last year.
A record 1,645 billionaires made the list this year with a total worth of $6.4 trillion, up from $5.4 trillion last year. In order to get into the top 20, a billionaire would have to at least $31 billion or more, up from $23 billion last year, Forbes said.
Other notable Americans on the list were Warren Buffet at No.4 with $58.2 billion and gambling tycoon Sheldon Adelson at No.8. Facebook founder Mark Zuckerberg gained the most, more than doubling his personal fortune to $28.5 billion, boosted by a sharp rise in the price of the social network's shares. His colleague Sheryl Sandberg also made this list for the first time.
WhatsApp founders Jan Koum and Brian Acton also make an appearance at at number 202 and 551 respectively, thanks to Mark Zuckerberg and Facebook's acquisition of the messaging app.
The U.S. had the most billionaires with 492, followed by Europe with 468 billionaires. Asia closely followed Europe with 444 billionaires, with a few African billionaires making an entry on the list. Four new countries featured on the list for the first time -- Algeria, Lithuania, Tanzania and Uganda -- suggesting that global wealth has started spreading to developing regions.
Women billionaires on the list increased this year from 172 versus 138 in 2013, representing an increase of 25 percent. the highest ranked woman was Christy Walton, the widow of John T. Walton, one of the sons of Sam Walton, the founder of Walmart, at number 9 with a net worth of $36.7 billion.