What is Multidistrict Litigation (MDL)?

MDL is a federal court procedure that groups similar lawsuits together before a single judge for the pretrial phase of litigation. It's designed to handle complex cases more efficiently when hundreds or thousands of people have filed similar claims against the same defendant. Understanding how MDL works can help you navigate your legal options and know what to expect as your case moves forward.

The Basics: What MDL Means

Multidistrict litigation is a procedural tool that allows federal courts to transfer civil cases filed in different districts to a single court when those cases share common factual questions. The transferee court handles all pretrial matters, including discovery (the exchange of evidence between parties), motions, and often settlement negotiations.

The key word is "pretrial." Under the statute that created MDL, cases are supposed to be sent back to their original courts for trial once pretrial proceedings conclude. In practice, the vast majority of MDL cases settle before reaching trial, so remand rarely happens.

A Brief History of MDL

Congress created multidistrict litigation in 1968, but the concept emerged from a crisis that began nearly a decade earlier.

The Electrical Equipment Scandal

In 1960, a federal grand jury indicted 45 executives from major electrical equipment manufacturers, including General Electric and Westinghouse, for conspiring to fix prices on equipment used by power companies. The criminal prosecutions resulted in significant fines and prison sentences for several executives.

After the criminal cases concluded, a flood of private civil lawsuits followed. More than 1,900 separate lawsuits were filed in 36 different federal court districts, together alleging over 25,000 claims involving 20 product lines. The federal court system faced an unprecedented challenge: how to manage thousands of related cases efficiently.

The Solution and MDL Statute

In 1962, Chief Justice Earl Warren appointed a special "Coordinating Committee for Multiple Litigation" (CCML), which developed innovative solutions that remain central to MDL practice today. The committee successfully cleared the electrical equipment backlog by March 1967, with only nine cases going to trial.

Congress enacted 28 U.S.C. § 1407 on April 29, 1968, signed into law by President Lyndon B. Johnson. The statute established the Judicial Panel on Multidistrict Litigation (JPML) as a permanent body to handle consolidation decisions.

The Judicial Panel on Multidistrict Litigation

The JPML is the gatekeeper for all MDL proceedings. Understanding its role is essential to understanding how MDL works.

Composition

The JPML consists of seven federal judges appointed by the Chief Justice of the United States. No two panel members may be from the same federal circuit, ensuring geographic diversity. The concurrence of at least four panel members is required for any action.

What the JPML Decides

How MDL Works: Step by Step

Understanding the MDL process helps plaintiffs know what to expect as their cases move through the system.

1. 1
   Individual Lawsuits Are Filed: MDL begins with individual plaintiffs filing separate lawsuits in federal courts across the country when many people are injured by the same product, drug, or conduct.
2. 2
   Someone Requests Consolidation: Once multiple related cases exist in different federal districts, any party can ask the JPML to consolidate them. Alternatively, the Panel may initiate the process itself.
3. 3
   The JPML Evaluates and Decides: The Panel considers whether cases share common factual questions. If granted, it issues a transfer order specifying the transferee court and judge.
4. 4
   Cases Are Transferred: All pending cases meeting the criteria are transferred. New cases filed afterward ("tag-along actions") are also transferred to keep all related litigation together.
5. 5
   The MDL Court Organizes: The transferee judge appoints a Plaintiffs' Steering Committee (PSC), establishes discovery schedules, sets deadlines, and creates procedures for managing thousands of cases.
6. 6
   Pretrial Proceedings: The MDL court handles discovery, motions, Plaintiff Fact Sheets, and Daubert hearings on expert testimony. These rulings often apply to all cases.
7. 7
   Bellwether Trials: Many MDL courts select representative cases for trial to help both sides evaluate claims and establish a framework for settlement negotiations.
8. 8
   Settlement or Remand: Most MDL cases resolve through settlement. Cases that don't settle are supposed to be remanded, but fewer than 3% of MDL cases are actually remanded.

MDL by the Numbers

MDL has grown from a specialized procedure to a dominant feature of federal civil litigation.

This represents dramatic growth. In 2012, MDL cases constituted only 29% of the civil docket. The percentage has more than doubled in just over a decade. The largest MDLs typically involve pharmaceutical products, medical devices, consumer products, and environmental contamination.

Interested in completed cases? See our archive of 30 MDLs that closed in 2025, including landmark cases like 3M Earplugs (MDL-2885) and DuPont PFOA (MDL-2433).

What MDL Means for Your Case

If your lawsuit becomes part of an MDL, several things change about how your case proceeds, though fundamental rights remain protected.

MDL vs. Trial Consolidation

It's important to understand what MDL is not. MDL consolidates cases for pretrial proceedings only. This is fundamentally different from consolidating cases for trial.

In trial consolidation (under Federal Rule of Civil Procedure 42), cases are combined for all purposes, including trial, and a single verdict may apply to all consolidated cases. MDL preserves each case's separate identity and, at least in theory, each plaintiff's right to their own trial.

For more on how MDL differs from class actions, see our detailed guide: MDL vs. Class Action: Key Differences Explained.

Frequently Asked Questions