Chelsea have lodged an appeal with the Court of Arbitration for Sport against the transfer ban issued by FIFA.
The game's global governing body issued the sanction in February as punishment for Chelsea's transfer of young foreign players.
"The Court of Arbitration for Sport (CAS) has registered an appeal filed by Chelsea Football Club Ltd (CFC) against the Federation Internationale de Football Association (FIFA)," read a statement.
The ban prohibits Chelsea from signing players during the 2019 summer and January 2020 transfer windows.
The Europa League champions have taken their case to CAS after FIFA rejected their appeal.
"The appeal is directed against the FIFA Appeal Committee decision dated 11 April 2019 in which CFC was declared liable for violations of the FIFA Regulations on the Status and Transfer of Players and banned from registering new players, nationally and internationally, for two entire and consecutive registration periods," the CAS statement read.