The new deal, worth $1.5 million, will tie Richt to the university through the 2010 season. He had four years remaining on a five-year contract that would have paid him $800,000 per season.
Richt earned the hefty raise by posting a 20-5 record in two seasons at Georgia. The Bulldogs are 12-1 this season, and won their first SEC title since 1982.
"Certainly Mark has done a remarkable job in just two years and has made a very positive impression on those at the university, in the community and state, and even nationally," said Georgia Athletic Director Vince Dooley. "And while the new contract in many ways is a reward, it is also an expression of the faith and confidence we have in him for the future."
The contract reportedly has a provision that will make it more difficult for Richt to leave.
The Atlanta Journal-Constitution reported that it includes a $1.5 million buyout, meaning a school would have to pay Georgia that much more money to hire Richt away.
Georgia, ranked fourth in the USA Today/ESPN coaches poll, will play Florida State in the Sugar Bowl on Jan. 1.
"This has been an overwhelming experience these first two years and there's no place I'd rather be," Richt said. "We went to be here as long as Georgia will have us."
Richt, 42, was an assistant at Florida State for 14 seasons before coming to Georgia.