Mixed Martial Arts Weight Classes - United States

United States

Prior to state sanctioning, weight classes were not mandatory since the competitions were held without the approval of the athletic commissions. For instance, the Ultimate Fighting Championship introduced two weight classes at UFC 12: heavyweight, which grouped competitors above 200 lb (91 kg), and lightweight, which grouped competitors under 200 lb.

Weight divisions underwent many changes in the ensuing years, but the ability of promotions to autonomously decide their own weight classes eventually disappeared after athletic commissions began supervising mixed martial arts.

In 2000, the Unified Rules of Mixed Martial Arts were codified by the New Jersey State Athletic Commission. The California State Athletic Commission had worked extensively on regulation, but their sanctioning of MMA was not implemented due to state governmental issues surrounding the process. California officially sanctioned MMA on December 28, 2005, using the ruleset it helped devise five years previously.

Since then, to create uniformity, all state commissions in the United States that regulate mixed martial arts have assimilated these rules into their existing unarmed combat competition rules and statutes. For a promotion to hold mixed martial arts events in a state-sanctioned venue, the promotion must abide by the state athletic commission's body of rules for weight limits.

In July 2008, a change to the existing classes was proposed to the Association of Boxing Commissions to expand the weight classes to 14, with most classes 10 pounds apart and a division of the current 205–265 lb heavyweight class into two. The proposals were met with resistance from various quarters, including from the UFC and several state athletic commissions. The proposed classes were later rejected by the ABC.