Sam Vasquez, 35, of Houston, was injured at the Toyota Center on Oct. 20 and died Friday. The Harris County Medical Examiner's Office confirmed Vasquez's death, but spokeswoman Stacey Mitchell said it could be several days before the official cause is determined.

Mixed martial-arts fighting, a free-for-all combination of judo, boxing, karate, Muay Thai, kickboxing, tae kwon do, jiujitsu and wrestling, has grown in popularity and attracted large pay-per-view television audiences.

To broaden its fan base, the sport has limited the violence, attracting new fans without alienating its original hard-core base.

Vasquez was hospitalized after he was knocked out by Vince Libardi of San Antonio in the third round of a fight at the Renegades Extreme Fighting show. He lost consciousness and suffered a seizure.

A call to the Texas Department of Licensing and Regulation, which sanctioned the fight, was not immediately returned today. The agency requires all competitors to be medically clearly to fight.

Saul Soliz, the Renegades promoter, has been staging professional and amateur shows in the state since 2000 and had the necessary license to stage the event.

Soliz did not immediately return a call today from The Associated Press, but in a statement sent through his lawyer, he said he was saddened by Vasquez's death.

"He was a great husband, father, son, brother, friend and martial artist," the statement said.

A mixed martial arts fan Web site said Vasquez was the first such fighter to die from an injury incurred or aggravated while competing in a regulated bout, though no official statistics were available. In 1998, American Doug Dedge died after being knocked out in an unregulated fight in the Ukraine.

Vasquez had been in intensive care at St. Joseph Medical Center before being transferred to a hospice last week.

Vasquez suffered a massive stroke while hospitalized. Comments attributed to his wife, Sandra, on the mixed martial arts forum www.txmma.com indicated he had been in a medically induced coma and had undergone two surgeries to remove blood clots in his brain.