The club is now free to sign new players in the January transfer window after a FIFA-imposed ban was reduced on appeal by the Court of Arbitration for Sport.
Chelsea won its appeal against a second FIFA transfer ban at the Court of Arbitration for Sport on Friday, allowing the English club to sign new players in January.
FIFA imposed a one-year ban on Chelsea registering new signings for breaking rules that protect youth players. The club already served one half of the FIFA ban when it was unable to register new players in the off-season.
CAS published its verdict two weeks after an appeal hearing in Lausanne. The ruling was needed before the next European player trading window opens on January 1.
A FIFA investigation ruled the Premier League club violated 150 rules protecting minors involving about 70 players.
Chelsea also broke rules prohibiting third-party influence on players.
CAS said Chelsea violated rules in a "significantly smaller" number of cases than FIFA said, and that the violations were less serious than previously judged.
CAS also halved the fine that FIFA imposed, so Chelsea will have to pay only $303,000 (300,000 Swiss francs).