Multidistrict litigation (MDL) is a procedure utilized in the federal court system to transfer to one federal judge all pending civil cases of a similar type filed throughout the United States. The decision whether cases should be transferred is made by a panel of seven federal judges appointed by the Chief Justice of the United States Supreme Court. The Judicial Panel on Multidistrict Litigation meets periodically to review requests that cases be consolidated for pretrial matters pursuant to 28 U.S.C. § 1407, a law passed by Congress. Although the panel meets in different cities in the United States on a periodic basis, the Clerk of the Panel is permanently stationed in Washington, D.C.

The judge who gets all the federal cases assigned to him is known as the “transferee judge.” The judges from throughout the United States who send cases to the MDL judge are known as the “transferor judges” or “transferor courts.”