UFC 13 featured two four man tournaments, a heavyweight tournament for fighters 200 lb or more, and a lightweight tournament for fighters under 200 lb, as well as two alternate bouts and a Superfight between Vitor Belfort and Tank Abbott.
This was the first appearance of two future UFC Champions and UFC Hall of Fame members Randy Couture and Tito Ortiz, who was an alternate in the lightweight tournament.
The show also featured the first and only UFC appearance of Tony Halme who had previously been a professional wrestler with World Wrestling Entertainment (then World Wrestling Federation) under the name of Ludvig Borga.
Bruce Buffer returned to announce the fights, after making his initial debut as an announcer at UFC 10.
This was the second UFC event to have two tournaments instead of one following UFC 12.