The Football Association and the Premier League announced today that they will hold a joint inquiry.
"The inquiry will be carried out by both the FA and the FAPL as the allegations relate to both FA and FAPL rules," said a statement.
Leeds made their complaint to the Football League on August 3.
Ken Bates claims his former club signed youngsters Michael Woods and Tom Taiwo after making illegal approaches.
Chelsea have offered £200k compensation for Woods and Taiwo, but Bates called it "insulting".
The Stamford Bridge club deny making illegal approaches.
Chelsea have filed a complaint with the Football Association against Bates, who they say has made "rude, insulting and inappropriate comments" during this dispute.
The Londoners could be docked three points if they are found guilty of illegal approaches to the Leeds youngsters.