CBS announced it has renewed Survivor and The Amazing Race and ordered additional installments for broadcast during the 2010-2011 primetime programming season.

Survivor's two-season renewal -- which will represent its 21st and 22nd installments -- come after Survivor: Samoa averaged 13.45 million total viewers and a 4.3/12 rating/share in the Adults 18-49 demographic last fall.

Survivor: Heroes vs. Villains, the show's 20th season and "10th anniversary edition," will premiere with a special two-hour episode on Thursday, February 11 at 8PM ET/PT and feature 20 former castaways competing for the title of "Sole Survivor."

The Amazing Race's seventeenth-season renewal comes after its fifteenth edition last fall averaged 11.91 million total viewers and a 3.7/09 rating/share in the Adults 18-49 demographic.

In addition, The Amazing Race claimed Outstanding Reality-Competition Program honors for the seventh year in a row at last September's 61st Annual Primetime Emmy Awards. It has won the award every year it has been presented.

The Amazing Race's sixteenth season will premiere on Sunday, February 14 at 8PM ET/PT.