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.
Chelsea 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.
Chelsea 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.
FIFA said in a statement: "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.
"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 and the FA for their responses.
Prior instances of similar infractions involving other clubs have seen the clubs involved appeal against the penalties, delaying the implementation of a registration ban and allowing them to sign players.