Tough to say, it's under dispute right now. The official score clock was started late so it is considered a KO before time.
http://www.YouTube.com/watch?v=TPxkEkGUeZU
as far as I know, Chris "The Menace" Clements vs Lautaro Tucas (3 seconds) is the one. You can find videos on that one, and it really is epic!
Kid Yamamoto has a lightning quick knee that knocked a guy out between 2-4 seconds.
The fastest UFC knockout was at UFC 102 by Todd Dufee against Tim Hague lasting only 7 seconds of the first round.
The fastest UFC Knockout is a tie with the fight from UFC 102 fight and now after last nights fights in Toronto. UFC 140 Chan Sung Jung aka Korean zombie Vs. Mark "the Machine" Hominick lasted only 7 seconds of the first round.
Cale Grady Knocked Out Ryan Chavarria in 2 sec. @ cage kings in shrevport Louisiana- in his first professional bout with one punch to rewrite the record books for the fastest ko in mma history.
In the UK recently a 6-second victory was recorded by Rob "chuck" Norris KO'ing Gavin Neaverson with 1 punch at the Caged Fighters 2 show in Leeds on 13/04/2012.
Records are a bit spotty especially from the early days. There are many local promotions almost no one ever hears of where guys fight for small purses and rack up giant records. One such fighter is Travis Fulton who has recorded 34 KOs and has a crazy record of 186-45-9. I suppose when one is getting paid $500 a fight, he must fight very often to make a living. Travis has no KOs over any well known, top ranked fighters though.
If you're looking for someone with KOs mostly in a large scale promotion then Anderson Silva would be up there with 14 (giving him a 58% win by KO ratio).
Liddell is close behind with 13.
Unofficially, Duane "Bang" Ludwig has a knockout of 6 seconds against Jonathan_Gouletat UFC Fight Night 3, even though the "official" time was 11 seconds. But the UFC are working to correct the error.
No, Ronda is undefeated in MMA, having won 12 fights (3 by knockouts and 9 by armbar submission). She is the first and current UFC Women's Bantamweight Champion.
Officially the record holder is Primo Carnera with 69 knockouts. But the legitimacy of some of them is highly dubious as Carnera's career was controlled by the mob and many if not most of his fights were allegedly fixed. George Foreman is second overall and first in legitimate knockouts with 68. Ezzard Charles (58) and Max Baer (52) are the only other heavyweights with more than 50 career knockouts. However, many of Charles' knockouts came in lower weight classes so there is some debate as to whether he should be on the list.
Chuck Liddel has 21 fights in the UFC with 28 fights overall.
according to Dana White, most likely UFC 95
UFC has always been UFC
There are a number of places where one can watch videos of the best knockouts in the UFC during 2008. The most extensive range of videos can be seen on the YouTube website. Other sites include Cage Potato and the official UFC website.
UFC Ultimate Knockouts 3 - 2004 V is rated/received certificates of: Australia:M
Steve Nelmark has: Played himself in "UFC 9: Motor City Madness" in 1996. Played himself in "UFC: Ultimate Ultimate 1996" in 1996. Played Himself archieve footage in "UFC Hits: Volume 1" in 2000. Played Himself archieve footage in "UFC 45: Revolution" in 2003. Played himself in "UFC: Ultimate Knockouts" in 2003. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007.
Gan McGee has: Played himself in "UFC 28: High Stakes" in 2000. Played himself in "UFC 39: The Warriors Return" in 2002. Played himself in "UFC 41: Onslaught" in 2003. Played himself in "UFC 44: Undisputed" in 2003. Played himself in "UFC: Ultimate Knockouts 3" in 2004. Played himself in "FightZone Presents" in 2007. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007.
No, Ronda is undefeated in MMA, having won 12 fights (3 by knockouts and 9 by armbar submission). She is the first and current UFC Women's Bantamweight Champion.
Wes Sims has: Played himself in "UFC 43: Meltdown" in 2003. Played himself in "UFC 46: Supernatural" in 2004. Played himself in "UFC: Ultimate Knockouts 3" in 2004. Played himself in "The Ultimate Fighter" in 2005. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007. Played himself in "MMA H.E.A.T." in 2009. Performed in "Apparitions: The Darkness" in 2009. Played himself in "Strikeforce: Miami" in 2010.
Hermes Franca has: Played himself in "UFC 44: Undisputed" in 2003. Played himself in "UFC 42: Sudden Impact" in 2003. Played himself in "UFC 46: Supernatural" in 2004. Played himself in "UFC: Ultimate Knockouts 3" in 2004. Played himself in "UFC 61: Bitter Rivals" in 2006. Played himself in "UFC: Fight Night 8" in 2007. Played himself in "UFC 73: Stacked" in 2007. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007. Played Himself - Guest in "FightZone Presents" in 2007. Played himself in "UFC: Silva vs. Irvin" in 2008. Played himself in "UFC 103: Franklin vs. Belfort" in 2009.
it depends on what you prefer if all you want is knockouts from a punch then get fight night if you want to throws punches kicks knees and throw in some jui jitsu get ufc 2009
Caol Uno has: Played himself in "UFC 30: Battle on the Boardwalk" in 2001. Played himself in "UFC 32: Showdown in the Meadowlands" in 2001. Played himself in "UFC 39: The Warriors Return" in 2002. Played himself in "UFC 37: High Impact" in 2002. Played himself in "UFC 41: Onslaught" in 2003. Played himself in "UFC 44: Undisputed" in 2003. Played himself in "UFC: Ultimate Knockouts 3" in 2004. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007. Played himself in "Dream. 3: Lightweight GP 2008 Second Round" in 2008. Played himself in "Dream. 5: Lightweight GP 2008 Final Round" in 2008. Played himself in "UFC 99: The Comeback" in 2009. Played himself in "UFC Fight Night: Florian vs. Gomi" in 2010. Played himself in "Dream. 17" in 2011.
Joe Louis (5 first round knockouts).
Yves Edwards has: Played himself in "UFC 33: Victory in Vegas" in 2001. Played himself in "UFC 45: Revolution" in 2003. Played himself in "UFC 43: Meltdown" in 2003. Played himself in "UFC 41: Onslaught" in 2003. Played himself in "UFC: Ultimate Knockouts 3" in 2004. Played himself in "UFC 49: Unfinished Business" in 2004. Played himself in "UFC 58: USA vs. Canada" in 2006. Played himself in "UFC 61: Bitter Rivals" in 2006. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007. Played himself in "Elite XC" in 2007. Played himself in "Strikeforce: Destruction" in 2008. Played himself in "Bellator Fighting Championships" in 2009. Played Bronner in "Circle of Pain" in 2010. Played himself in "Moosin: God of Martial Arts" in 2010. Played Houston Greggs in "Warrior" in 2011.
David Terrell has: Played Thomas Reedy in "Shallow Ground" in 2004. Played himself in "UFC Unleashed" in 2005. Played himself in "UFC 51: Super Saturday" in 2005. Played Himself - Middleweight Fighter in "UFC 59: Reality Check" in 2006. Played himself in "UFC: Ultimate Ultimate Knockouts" in 2007.