King of the Cage 3: Knockout Nightmare was a mixed martial arts event that took place on April 15, 2000 at the Soboba Casino in San Jacinto, California. Ironically, two thirds of the fights were not ended by knockout or TKO.
- Barrazza submitted Cahill via rear naked choke at 2:01 of Round 1.
- Step submitted Mondo via armbar at 1:32 of Round 1.
- Ludwig defeated Maxwell via decision.
- Stevenson defeated Imada via decision.
- Abrille submitted Conrad via heel hook at 0:37 of Round 1.
- Sullivan submitted McWatters via heel hook at 1:33 of Round 1.
- Kerns submitted Asencio via choke at 1:34 of Round 1.
- Vazquez submitted Emae at 2:44 of Round 1. Vazquez mounted Emay and Emay could not escape, so he tapped. The official record at Sherdog says "Submission (injury)".
- Dullanty TKO Shad via strikes at 1:58 of Round 1.
- Bourke TKO Treadwell via corner stoppage at 1:46 of Round 1.
- Brennan knocked out McKee via a kick to the head at 0:09 of Round 2.
- White knocked out Medina via a punch at 0:09 of Round 1.