Multidistrict litigation is a legal procedure in United States federal courts in which lawsuits involving similar issues (common issues of fact) are consolidated in one court (called the MDL court) for the purpose of convenience and efficiency in pretrial matters, such as discovery. These lawsuits are generally returned to their original federal district courts for trial. Claims that are often the subject of multidistrict litigation are product liability claims against pharmaceutical companies, securities fraud cases, and airplane crashes.

In Massachusetts, as in other states, multidistrict litigation (MDL) is a federal legal procedure that consolidates multiple lawsuits involving common factual issues to improve efficiency and convenience during pretrial proceedings. This process is governed by federal law, specifically 28 U.S.C. § 1407, and is not unique to any one state. The Judicial Panel on Multidistrict Litigation (JPML) decides whether cases should be transferred to an MDL court. While pretrial activities, including discovery and motions, are centralized, the individual cases are typically sent back to their original courts for trial. MDLs are commonly used for complex cases such as product liability suits, including those against pharmaceutical companies, securities fraud cases, and major accident litigation like airplane crashes. It's important to note that while the MDL process is federal, cases that originate in Massachusetts federal courts can be part of an MDL, and Massachusetts attorneys may be involved in these proceedings.