Chelsea have been banned from signing players for the next two transfer windows after FIFA found them guilty of breaching rules relating to the signing of players under the age of 18.
It means Chelsea cannot sign players until the summer of 2020, but does not affect their ability to release players or bring back loan players.
FIFA said Chelsea had been found to have “breached article 19 of its regulations in the case of 29 minor players and to have committed several other infringements relating to registration requirements for players.”
It added that the club had also “breached article 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 club have also been fined £460,000 ($599,000) and given 90 days to “regularise the situations of the players concerned.”
Last month it emerged that FIFA’s investigation into Chelsea’s transfer dealings had widened to examine arrangements with more than 100 foreign players under the age of 18.
However, the club said many of the individual cases highlighted involved players on short-term trials who were not signed.
They can contest the judgment with the FIFA appeals committee and, ultimately, would have the right to take it to the Court of Arbitration for Sport.
FIFA also found the Football Association in breach of its transfer regulations, fining it £390,000 and giving it “a period of six months to address the situation concerning the international transfer and first registration of minors in football.”
An FA spokesman said the organisation attended to appeal against the FIFA punishment and would “continue to work with FIFA and Chelsea in a constructive manner to address the issues which are raised by this case.”