|Pat Miletich||October 16, 1998||Sao Paulo, Brazil||-a-|
|Carlos Newton||May 4, 2001||Atlantic City, New Jersey|
|Matt Hughes||November 2, 2001||Las Vegas, Nevada|
|B.J. Penn||January 31, 2004||Las Vegas, Nevada||-b-|
|Matt Hughes ||October 22, 2004||Atlantic City, New Jersey||-c-|
|Georges St. Pierre||November 18, 2006||Sacremento, California|
|Matt Serra||April 7, 2007||Houston, Texas|
|Georges St. Pierre ||December 29, 2007||Las Vegas, NV||-d-|
|Georges St. Pierre ||April 19, 2008||Montreal, Quebec||-e-|
-a- Defeated Mikey Burnett to win the title.
-b- Title vacated in October of 2004 when Penn signs with K-1.
-c- Defeated Georges St. Pierre to win the vacant title. Title again vacated in 2005.
-d- Defeated Matt Hughes for the interim title.
-e- Defeated Matt Serra for the undisputed title.