Zurich - FIFA on Thursday dismissed appeals by Real Madrid and Atletico Madrid against a ban on registering new players in the next two transfer windows for irregularities in the signing of foreign players under 18.
Real and Atletico -- last season's Champions League finalists -- were also fined 360,000 ($358,000) and 900,000 Swiss Francs respectively.
However, the Spanish giants still have a final right of appeal to the Court of Arbitration for Sport (CAS).
"The FIFA Appeal Committee has decided to reject the appeals lodged by Spanish clubs Atletico de Madrid and Real Madrid and to confirm in their entirety the decisions rendered by the FIFA Disciplinary Committee in the respective cases relating to the protection of minors," FIFA said in a statement.
Both clubs were sanctioned in January, but by appealing had temporarily held off the ban during the transfer window which closed last month.
They will now not be able to register any new players in either of the next two windows, in January 2017 and July-August 2017.
European champions Real responded by saying they will now go to the CAS in an attempt to have the decision overturned "as quickly as possible".
"The club regrets the decision on the ground that it is profoundly unfair and contrary to the most elementary principles of penal law," read a statement posted on their website.
"The club will begin the appropriate appeals procedure before the Court of Arbitration for Sport, requesting that the decision be completely overturned, with absolute confidence that said organisation will come to an entirely favourable decision.
"Real Madrid C. F. will request that the procedure be undertaken in an urgent manner in order to obtain a decision from the CAS as quickly as possible."