"We are all shocked and saddened by the devastating and untimely loss of Kimbo Slice, a beloved member of the Bellator family," Bellator MMA president Scott Coker said.
"One of the most popular MMA fighters ever, Kimbo was a charismatic, larger-than-life personality that transcended the sport."
"Outside of the cage he was a friendly, gentle giant and a devoted family man. His loss leaves us all with extremely heavy hearts, and our thoughts and prayers are with the entire Ferguson family and all of Kimbo's friends, fans, and teammates."
Slice first rose to fame through videos of street fights posted online. He later turned that fame into a professional mixed marital arts fighting career.
Slice, whose real name was Kevin Ferguson, was admitted earlier Monday to a Florida hospital, according to multiple media reports.
A Coral Springs, Fla. Police sergeant told The Associated Press earlier Monday after Slice had been hospitalized that no foul play was suspected. Officers had been dispatched to his home in anticipation of a crowd gathering there.
The ATT Family and South Florida community lost a legend today. RIP Kimbo. pic.twitter.com/sjs8ctyJMd— American Top Team (@AmericanTopTeam) June 7, 2016
Slice (5-2) had been scheduled to fight James Thompson on July 16 in Bellator 158 in London.
He last fought at Bellator 149 on Feb. 19 in Houston. His win was later changed to a no-contest by the Texas commission, after Slice tested positive for anabolic steroids and an elevated testosterone ratio.