What is multidistrict litigation (mdl)?

Multidistrict litigation, or MDL, is a federal procedure that consolidates similar lawsuits filed in different districts before a single judge for coordinated pretrial proceedings, such as discovery and expert rulings, to avoid duplicative work and inconsistent rulings. An MDL is not itself a class action — individual cases keep their own identity and typically get sent back to their home court for trial if they are not resolved first.

MDLs and class actions are often confused because both involve many claimants and a single coordinating court, but an MDL is a collection of individual lawsuits managed together, while a class action is legally one case brought on behalf of a group. Mass tort injury cases — defective drugs or devices, for example — are more often handled as MDLs than as class actions, since individual damages tend to vary too much for class treatment. The U.S. Judicial Panel on Multidistrict Litigation decides whether to consolidate related cases and where.

Last reviewed 2026-08-22.