As of 2012, Carlos Slim is the richest person in the world. He is Mexican and a business magnate and has been named among the wealthiest individuals for three consecutive years. Check out http://en.wikipedia.org/wiki/Carlos_Slim for more information.
I believe it's Carlos.Carlos Slim Helu was named the world's richest person by Forbes Magazine in 2011, with a fortune of $74 billion. Bill Gates is the richest in the United States with $56.0 billion.