At the time of the UFC's inception in 1993,
Mixed martial arts was not sanctioned in the United States, and did not include
weight classes. Instead of the traditional championship model, the UFC held tournaments with the winner receiving a permanent appellation. In
response to criticism from Senator
John McCain that saw the loss of its television deal and the banning of the sport in thirty-six states, the UFC increased its cooperation with state athletic commissions and introduced weight classes in 1997, starting with
UFC 12, and began introducing weight-specific titles. The original codification for weight classes introduced only two divisions:
heavyweight, which grouped together all competitors above , and
lightweight, which encompassed all competitors 199 pounds (90 kg) and under. At
UFC 14 the
lightweight division would be renamed to
middleweight, though it would still encompass all fighters 199 pounds (90 kg) and under. Two years later a fourth weight class, the
bantamweight division, arrived at
UFC 26 and included all fighters and under. In 2000, the
New Jersey State Athletic Control Board completely took over MMA regulation in its home state and developed new
rules and weight classes that eventually became the
de facto rule set for all mixed martial arts. The UFC realigned their weight classes to comply with these new regulations in 2001, beginning with
UFC 31. At the time, this brought the total number of active divisions in the UFC to five:
lightweight,
welterweight,
middleweight,
light heavyweight, and
heavyweight. It would be nearly ten years before the UFC would expand their divisional offerings to include any of the lower weight classes. The first additions came in late 2010 when the UFC merged with their sister organization
World Extreme Cagefighting (WEC). Due to the WEC's focus on lighter weight fighters, this merger necessitated the addition of both the
featherweight and
bantamweight divisions to the UFC, starting with
The Ultimate Fighter season 12 finale. In early 2012 the UFC decided they would delve even further into the lower weight classes when they announced the introduction of the
flyweight division to their ranks, beginning with
UFC on FX: Alves vs. Kampmann. In November 2012, as a result of the forthcoming dissolution of their sister organization
Strikeforce, the UFC announced they would be adding female fighters to their roster for the first time in the promotion's history. Initially, only the women's bantamweight division was brought over, with the division's premiere bout taking place at
UFC 157. A little over a year later, the UFC announced they would be expanding their weight classes for female fighters with the addition of a women's
strawweight division, the first bout took place at
UFC Fight Night: Cowboy vs. Miller. In late 2016, a featherweight division was introduced for the women with the first bout to be for the
inaugural championship at
UFC 208 on February 11, 2017. In that same year the UFC announced the Women's Flyweight division would officially be added, with the winner of the
26th season of The Ultimate Fighter to be named the inaugural champion. ==Current champions==