(a) If a complete determination of a controversy cannot be had without the presence of other parties, the court may direct them to be brought in. If a person, not a party, has an interest or title which the judgment may affect, the court, on application, shall direct such person to be made a party.
2-406.Bringing in new parties - Third-party proceedings.
Article II. Civil Practice · Part 4. Parties · Not amended since adoption on record · Last verified July 20, 2026
In one sentenceSection 2-406 lets a court bring in additional parties needed for a complete resolution, lets a defendant file a third-party complaint against someone who may owe them for the plaintiff's claim, and explains how an action against a new party formally begins.
Full Text of 735 ILCS 5/2-406
(b) Within the time for filing his or her answer or thereafter by leave of court, a defendant may by third-party complaint bring in as a defendant a person not a party to the action who is or may be liable to him or her for all or part of the plaintiff's claim against him or her. Subsequent pleadings shall be filed as in the case of a complaint and with like designation and effect. The third-party defendant may assert any defenses which he or she has to the third-party complaint or which the third-party plaintiff has to the plaintiff's claim and shall have the same right to file a counterclaim or third-party complaint as any other defendant. If the plaintiff desires to assert against the third-party defendant any claim which the plaintiff might have asserted against the third-party defendant had he or she been joined originally as a defendant, the plaintiff shall do so by an appropriate pleading. When a counterclaim is filed against a party, the party may in like manner proceed against third parties. Nothing herein applies to liability insurers.
(c) An action is commenced against a new party by the filing of an appropriate pleading or the entry of an order naming him or her a party. Service of process shall be had upon a new party in like manner as is provided for service on a defendant.
Plain-English Summary
If a controversy can't be fully resolved without other parties, the court can direct that they be brought in, and must do so, on application, if a nonparty holds an interest or title that the judgment might affect.
A defendant can also bring in a new party through a third-party complaint — filed within the time to answer or later with leave of court — against someone not already in the case who is or may be liable to the defendant for all or part of the plaintiff's claim. Later pleadings in that branch of the case follow the same rules as a complaint. The third-party defendant can raise any defense available against the third-party complaint or that the third-party plaintiff has against the original claim, and can counterclaim or bring in further third parties just like any other defendant. If the plaintiff wants to bring a claim directly against the third-party defendant that could have been asserted had that party been an original defendant, the plaintiff does so through an appropriate pleading. A party facing a counterclaim can proceed against third parties the same way. None of this applies to liability insurers.
An action against a new party formally begins when an appropriate pleading is filed or when the court enters an order naming that person a party, and service of process on a new party follows the same procedure used for serving a defendant.
Frequently Asked Questions
When will a court order additional parties brought into a case?
When a complete determination of the controversy can't be had without them. If a nonparty holds an interest or title the judgment may affect, the court must direct, on application, that the person be made a party.
What is a third-party complaint under this section?
It's a pleading a defendant files, within the time to answer or later with leave of court, bringing in a person not already a party who is or may be liable to the defendant for all or part of the plaintiff's claim.
What can a third-party defendant do once brought into the case?
The third-party defendant may assert any defense available against the third-party complaint or that the third-party plaintiff has against the plaintiff's claim, and has the same right as any other defendant to file a counterclaim or bring in further third parties.
Can the plaintiff sue the third-party defendant directly?
Yes, if the plaintiff could have asserted that claim against the third-party defendant had that party been joined as an original defendant. The plaintiff does this through an appropriate pleading.
When does an action against a newly added party officially begin?
When an appropriate pleading is filed or the court enters an order naming the person a party, and service of process on that new party follows the same procedure used for serving a defendant.
Amendment History
(Source: P.A. 82-280.)
Source & verification. Section text and amendment history are
reproduced verbatim from the Illinois Compiled Statutes, published by the
Illinois Compiled Statutes, Illinois General Assembly / Legislative Reference Bureau. Last verified July 20, 2026.
· Official source
Also known as: third party complaint illinoisbringing in new parties to a lawsuitimpleader illinois civil procedure