Chelsea and the Football Association have been sanctioned by FIFA's disciplinary committee for breaching regulations over the transfer of minors, the world governing body has announced.
The Blues have been banned from registering players for two consecutive transfer windows for 29 incidences of breaching article 19, which relates to the transfer of players aged under 18.
The London club were also fined 600,000 Swiss francs (over £460,000), while the FA has been fined 510,000 Swiss francs (over £390,000) for breaching the rules in connection with minors.
Chelsea also twice breached regulations relating to third-party influence, article 18bis, FIFA said.
"The FIFA disciplinary committee has sanctioned the English club Chelsea FC and the Football Association for breaches relating to the international transfer and registration of players under the age of 18," FIFA's statement read.
"Chelsea was found to have breached art. 19 of the Regulations in the case of twenty-nine (29) minor players and to have committed several other infringements relating to registration requirements for players.
"The club also breached art. 18bis of the Regulations in connection with two agreements it concluded concerning minors and which allowed it to influence other clubs in transfer-related matters.
"The disciplinary committee sanctioned Chelsea with a ban on registering new players at both national and international level for the next two (2) complete and consecutive registration periods.
"This ban applies to the club as a whole – with the exception of the women's and futsal teams – and does not prevent the release of players."
Press Association Sport has contacted Chelsea for a response.
The FA indicated it would appeal against the decision.
A tweet from the @FAspokesperson account read: "The FA notes the decision of the FIFA Disciplinary Committee published today.
"The FA has co-operated fully with FIFA's investigations, although we have raised some concerns with FIFA regarding its disciplinary processes.
"The FA intends to appeal the decision. We will however continue to work with FIFA and Chelsea in a constructive manner to address the issues which are raised by this case.
"As this is an ongoing legal process it would not be appropriate to comment further at this time."