Gates, 56, whose net worth grew $7 billion from a year earlier to $66 billion in 2012, topped the list for the 19th year in a row.
He is followed by Berkshire Hathaway Inc.'s Buffett (No. 2) with $46 billion, also up $7 billion from last year, and Oracle Corp's Larry Ellison (No. 3) with $41 billion, up $8 billion—and the biggest dollar gainer this year.
Desai with a net worth of $2 billion as of September 2012 has been ranked 239 in Forbes' annual list released yesterday.
Desai, 59, started Syntel in 1980 with his wife while earning his MBA from the University of Michigan. An IIT Mumbai alumnus, Desai stepped down as chief executive of the firm in 2009 but remains chairman.
Founder and chairman of the Symphony Technology Group, Romesh Wadhwani is ranked 250 with a net worth $1.9 billion.
Google board member and shareholder Kavitark Ram Shriram occupies the 298th rank with a net worth of $1.6 billion. Manoj Bhargava, founder and CEO of the popular energy drink '5-hour energy' is ranked 311 and has a $1.5 billion net worth.
He is followed by Khosla on the 328th rank and a $1.4 billion net worth.
The net worth of the richest Americans grew by 13 per cent in the past year to $1.7 trillion, Forbes magazine said in a statement.
A graduate of Carnegie Mellon University and IIT Mumbai, Wadhwani, 65, developed business software firm Aspect Development which he sold in 2000 during the height of the tech bubble for $9.3 billion.
A "notable" newcomer on the list, Bhargava, 59, is a Princeton University drop out who "chose one of the roads less traveled to the American Dream".
Described as a math whiz, Bhargava lived as a monk in the mountains of India for 12 years before returning to the US to forge a successful career in plastics.
Forbes said Stanford and IIT alumnus Khosla, 57, "isn't afraid to fail”. His firm also had a stake in social enterprise software company Yammer, which was purchased by Microsoft in July for $1.2 billion.
A Google board member and large shareholder, Shriram, 55, has stakes in online outsourcer 24/7 Customer and serendipitous website picker StumbleUpon.
He also invested in Inkling, which makes interactive textbooks for the iPad.
He serves as a trustee at Stanford University, where he and his wife endowed the Shriram Family Professorship in Science Education.
Facebook founder Mark Zuckerberg has been pushed down in the rankings to the No. 36 spot with his estimated net worth falling by about $8 billion to $9.4 billion since Facebook went public in May.