The debut season of The Ultimate Fighter (later designated The Ultimate Fighter 1) premiered on January 17, 2005. Sixteen mixed martial arts fighters (eight light heavyweights weighing from 186 to 205 lb and eight middleweights weighing from 171 to 185 lb) were invited to participate in the show where they resided together and trained in two separate teams coached by UFC light heavyweight fighters Chuck Liddell and Randy Couture. The teams competed in physical challenges, segments hosted by singer Willa Ford, to determine which had the right to pair one of their fighters against an opponent of their choice in the same weight class, with the loser being eliminated.

The finale was broadcast live on April 9, 2005, where the two finalists in each weight class faced off for a contract with the UFC. It was the first live UFC broadcast on non-pay-per-view television, and it drew a very impressive 1.9 overall rating. The series was also broadcast in the United Kingdom in the spring of 2005 on Bravo. A 5-disc DVD set of "The Ultimate Fighter" was released on November 1, 2005.

Episode 1: "The Quest Begins" (original airdate: 17 January 2005)

Episode 2: "Team Challenges" (original airdate: 24 January 2005)

Episode 3: "Making Weight" (original airdate: 31 January 2005)

Episode 4: "On The Ropes" (original airdate: 7 February 2005)

Episode 5: "Un-Caged" (original airdate: 14 February 2005)

Episode 6: "The Fight Is On" (original airdate: 21 February 2005)