The UFC has threatened legal action against the U.S. Anti-Doping Agency (USADA) following a statement USADA made on Wednesday announcing an end to the partnership between the two organizations. The UFC's decision to leave USADA was due to the belief that it could put together a better program.

The dispute between the UFC and USADA began with Conor McGregor's status. In an interview with TSN in July, UFC president Dana White said, “Who cares what USADA says?” in reference to McGregor's status. McGregor's return announcement at UFC 296 raised concerns about USADA's integrity and authenticity by fans. McGregor found himself caught up in yet another controversy after word got out that he hasn't been tested by USADA this year. USADA CEO Travis Tygart issued a statement saying that the agency will cease being the UFC's anti-doping partner beginning Jan. 1, 2024. Tygart wrote that the UFC did an “about-face” on their relationship Monday due to USADA's stance on the status of Conor McGregor.

UFC chief business officer Hunter Campbell said at a news conference on Thursday that he sent a legal letter to USADA on Wednesday night accusing it of defamation and demanding that it issue a retraction. Campbell and UFC executive Jeff Novitzky also announced on Thursday that the UFC will use Drug Free Sport to collect drug-test samples beginning next year and the UFC's anti-doping program will be led by former FBI agent George Piro as an independent administrator. Campbell said what USADA did to McGregor was “disgusting” and there could be legal liability. In a three-page letter sent to USADA on Thursday from UFC's outside counsel, there was a claim of defamation and that the UFC has the right to assert such a claim “when the damaging comments negatively impact its reputation, integrity, and honesty, which is exactly what occurred here.”

The UFC's decision to leave USADA was due to the belief that it could put together a better program. USADA requested $7 million from the UFC for next year, which was not much more than the UFC had been paying the agency for each of the last eight years. Campbell told ESPN that there were indeed mentions of money in talks with USADA, but the UFC decided to leave USADA because of the belief it could put together a better program.