The English Premier League leaders had asked the Lausanne-based court for a stay until the result of an appeal was decided.
The CAS said in a statement that it had granted the request, with the sanctions suspended "until the CAS renders its final decision in this matter".
No date was given for the decision but one legal expert doubted a final verdict would be reached before March.
Chelsea were banned from registering any new players until January 2011 after being found guilty in September of inducing Gael Kakuta to break his contract with French club Racing Lens.
Kakuta was also banned from playing official matches for Chelsea for four months while the London club were ordered to pay compensation to Lens.
The punishment was handed out following a contractual dispute involving the transfer of reserve team player Kakuta, now 18, from Lens in 2007.
Midfielder Kakuta had been at Lens since he was eight, going through their schooling system. A France under-19 international, he made only five Chelsea youth team appearances last season and two for the reserves.
'TOTALLY DISPROPORTIONATE'
The English club, who have slammed the FIFA ban as "extraordinarily arbitrary" and "totally disproportionate", noted the CAS action on their website without further comment.
Manager Carlo Ancelotti batted off reporters' questions, saying Chelsea were concentrating on Sunday's home game against Manchester United and that the CAS situation would take care of itself.
Professor Ian Blackshaw, a lawyer who has worked for the CAS, told Sky Sports News that it could be some time before the matter was resolved.
"This means that Chelsea are free, if they wish to do so, to deal in the transfer market in January," he said.
"The key question now is when will CAS hear the appeal and finally decide?
"Under the CAS procedural rules, generally speaking an appeal must be decided within four months of the pleadings having been settled, the pleadings being the statement of appeal, the answer to the appeal, any submission made in the case by the FIFA dispute resolution chamber.
"I don't think we will get an appeal much before March or even April of next year."
Should Chelsea make signings in January, there could be further legal complications if the ban is subsequently upheld.
