If any such action is commenced without filing such written instrument, the court, on motion, shall dismiss the same, and the attorney of the plaintiff shall pay all costs accruing thereon, unless the security for costs is filed within such time as is allowed by the court, and when so filed it shall relate back to the commencement of the action; the right to require security for costs shall not be waived by any proceeding in the action.
5-103.Dismissal for want of security.
Article V. Costs · Not amended since adoption on record · Last verified July 20, 2026
In one sentenceDirects the court to dismiss an action commenced without the required security for costs, makes the plaintiff's attorney liable for costs already accrued, and lets late-filed security relate back to the case's start, while making clear the right to demand security is never waived just by proceeding in the case.
Full Text of 735 ILCS 5/5-103
Plain-English Summary
This section supplies the consequence for skipping the security-for-costs requirement described in Section 5-101. If such an action is commenced without filing the required written instrument, the court, on motion, dismisses it.
Along with dismissal, the plaintiff's attorney becomes responsible for paying all costs that accrued in the case, unless the security is filed within whatever time the court allows. When it is filed within that time, the filing relates back to the commencement of the action, so the case is treated as if security had been in place from the start.
The section closes with a protective rule for whoever is entitled to demand security: that right is not waived because the case has gone forward through some proceeding. Continuing to litigate doesn't forfeit the ability to insist on security later.
Frequently Asked Questions
What happens if a required security for costs is never filed before the action is commenced?
The court, on motion, dismisses the action.
Who pays the costs that accrued before the dismissal?
The plaintiff's attorney, unless the security for costs is filed within the time allowed by the court.
What happens if the plaintiff files security late, within a court-set deadline?
The late filing relates back to the commencement of the action.
Can a defendant lose the right to demand security for costs by letting the case proceed?
No. The section states the right to require security for costs is not waived by any proceeding in the action.
Does this section name who may bring the motion to dismiss?
No. It states only that the court acts "on motion," without identifying who must make that motion.
Amendment History
(Source: P.A. 83-707.)
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: dismissal for failure to post security for costs illinoisattorney liable for costs illinoisrelate back security for costs illinoiswaiver of right to demand security for costs