FIFA's appeals committee rejected the appeal filed by the Uruguayan Football Association (AUF), although it still can take the case to the Court of Arbitration for Sport (CAS), a FIFA spokeswoman said.
Suarez initially denied biting Chiellini but apologized nearly a week later.
“The truth is that my colleague Giorgio Chiellini suffered the physical result of a bite in the collision he suffered with me,” Suarez said in a statement on Twitter.
FIFA's disciplinary committee ruled that he acted intentionally and handed him the longest ban ever imposed on a player at the World Cup, prompting fury in his South American homeland, where he was given a hero's welcome on his return.
FIFA later explained that Suarez was given a heavy punishment partly because he had twice before been banned for biting and because he had shown no remorse.
The English Premier League club have since held talks in London over the possible transfer of Suarez to Barcelona, although no deal has been finalized.
Chiellini himself has described the ban as excessive.