Sepp Blatter and Michel Platini have lost their appeals against 90-day bans for alleged financial wrongdoing.
The provisional bans prevent Blatter from working as FIFA president and stop UEFA president Platini from campaigning for the FIFA presidential election on Feb. 26.
Platini and outgoing FIFA president Blatter were both provisionally suspended by FIFA's ethics committee in October over a £1.3 million ($2 million) payment made to Platini in 2011 for work said to have been carried out more than nine years previously.
FIFA Appeal Committee rejects appeals lodged by Joseph S. Blatter and Michel Platini against provisional bans - https://t.co/r2nka6IH3f
- FIFA Media (@fifamedia) November 18, 2015
Blatter was accused of making a "disloyal payment" to Platini, but both have denied any wrongdoing. They have acknowledged that there was no written contract for the extra salary, but say there was a verbal agreement.
Blatter's lawyers said he was disappointed by the decision and insisted there was no evidence of an improper conduct over the payment.
A statement said: "Noticeably absent from the opinion and these proceedings is any evidence of any improper motivation or purpose for the agreement between FIFA and Mr Platini.
"The appeal committee rendered this decision on Nov. 3 but released it only today, over two weeks later.
"President Blatter is committed to clearing his name and hopes this inexplicable delay is not an effort to deny him, during his elected term, a fair hearing before a neutral body.
"He will continue his appeals and looks forward to the opportunity to be heard, including through the presentation of evidence and argument of counsel, and thereby demonstrate he has engaged in no misconduct."
After the decision, Platini said he would take his case to the Court of Arbitration for Sport (CAS), in Lausanne, Switzerland, French news agency AFP reported.
The CAS decision will determine whether there is any remaining hope for Platini's bid to run for the FIFA presidency. Blatter could also choose to take his case to the CAS.
Platini's lawyers criticised what they described as a "uniquely one-sided, unjust and biased" investigation against him, and also claimed it had taken more than two weeks for them to be notified of the FIFA appeals committee verdict.
"[FIFA] is also organizing -- and is no longer even hiding it -- a deliberate and unacceptable strategy of delaying Michl Platini's campaign for the FIFA presidency," Clifford Chance, Platini's legal firm, said in a statement.
Platini, a former France captain, will not be considered by FIFA's electoral committee unless his ban is lifted, and no integrity check will be carried out until his case is resolved.
"This decision is not a surprise,'' Clifford Chance said in a statement, which noted that sport's highest court was free of "the pressures exerted within FIFA" and said Platini "has full trust in CAS to re-establish all of his rights."
The FIFA statement confirmed that the appeal committee, chaired by Larry Mussenden, had "rejected in full the appeals lodged by Joseph S. Blatter and Michel Platini."
According to the statement, the committee had "confirmed in their entirety the respective decisions (cf. art. 84 par. 2 of the FIFA Code of Ethics) concerning provisional measures taken by the adjudicatory chamber of the independent ethics committee."