UFC 137 took place Oct. 29 at the Mandalay Bay Events Center in Las Vegas with a Nick Diaz vs. B.J. Penn pay-per-view headliner.
The NSAC tested both of Diaz and Penn, as well as Cheick Kongo, Roy Nelson, Scott Jorgensen, Hatsu Hioki, Donald Cerrone, Eliot Marshall, Brandon Vera, Chris Camozzi, Francis Carmont, Ramsey Nijem, Danny Downes, Bart Palaszewski, Tyson Griffin, Dustin Jacoby and Clifford Starks.
All fighters tested negative for drugs of abuse such as marijuana and cocaine, as well as anabolic steroids and other performance-enhancers.