(a) Filing. When service of a document is required, proof of service shall be filed with the
clerk.
Rule 12.Proof of Service in the Trial and Reviewing Courts; Effective Date of Service
Article I. General Rules · Last amended 2017 · Last verified July 20, 2026
In one sentenceRule 12 explains how to prove that service was completed and pins down exactly when service becomes legally effective depending on the method used.
Full Text of Ill. S. Ct. R. 12
(b) Manner of Proof. Service is proved:
(1) in the case of electronic service through the court electronic filing manager or an approved electronic filing service provider, by an automated verification of electronic service, specifying the time of transmission and e-mail address of each recipient;
(2) in the case of service by e-mail, by certification under section 1-109 of the Code of Civil Procedure of the person who initiated the transmission, stating the date of transmission and the e-mail address of each recipient;
(3) by written acknowledgment from the person served;
(4) in case of service by personal, office, or residential delivery, by certification under
section 1-109 of the Code of Civil Procedure of the person who made delivery, stating the time and place of delivery;
(5) in case of service by mail or by delivery to a third-party commercial carrier, by certification under section 1-109 of the Code of Civil Procedure of the person who deposited the document in the mail or delivered the document to a third-party commercial carrier or courier, stating the time and place of mailing or delivery, the complete address that appeared on the envelope or package, and the fact that proper postage or the delivery charge was prepaid; or
(6) in case of service by mail by a self-represented litigant residing in a correctional facility, by certification under section 1-109 of the Code of Civil Procedure of the person who deposited the document in the institutional mail, stating the time and place of deposit and the complete address to which the document was to be delivered.
(c) Effective Date of Service. Service by electronic means or by personal, office, or residential delivery is complete on the day of transmission. Service by delivery to a third-party commercial carrier or courier is complete on the third court day after delivery of the package to the third-party carrier. Service by U.S. mail is complete four days after mailing.
Plain-English Summary
Rule 12 requires anyone who serves a document to file proof of that service with the clerk. How you prove service depends on the method: electronic service through the court's filing system is proved by an automated verification; service by email, personal delivery, or mail is proved by a sworn certification describing the time, place, and recipient.
The rule then fixes the effective date of service for each method. Electronic service and personal, office, or residential delivery are complete the day of transmission or delivery. Service through a commercial carrier is complete on the third court day after drop-off. Service by U.S. mail is complete four days after mailing.
Frequently Asked Questions
How do I prove I served a document electronically?
Through the court electronic filing manager's automated verification of service, or by your own certification stating the transmission date and recipient email address.
When is service by mail considered complete under Illinois rules?
Four days after mailing, regardless of when the recipient receives it.
Is proof of service required for every document I serve?
Yes, when service of a document is required, Rule 12 requires you to file proof of that service with the clerk.
When does electronic service become effective?
On the day of transmission.
How long after delivery to a carrier like FedEx is service complete?
On the third court day after the package is delivered to the third-party carrier.
Committee Comments
(December 29, 2009)
The rules on service and filing have been revised to provide for sending documents via third- party commercial carrier. Under these rules, the term “delivery” refers to all the carrier’s standard pick-up methods, such as dropping a package in a UPS or FedEx box or with a UPS or FedEx contractor.
Amendment History
Amended effective July 1, 1971, and July 1, 1975; amended October 30, 1992, effective November 15, 1992; amended December 29, 2009, effective immediately; amended Dec. 21, 2012, eff. Jan. 1, 2013; amended Jan. 4, 2013, eff. immediately; amended September 19, 2014, eff. immediately; amended Dec. 9, 2015, eff. Jan. 1, 2016; amended Oct. 6, 2016, eff. Nov. 1, 2016; amended June 22, 2017, eff. July 1, 2017.
Source & verification. Rule text, official Committee Comments, and
amendment history are reproduced verbatim from the Illinois Supreme Court Rules,
promulgated by the Supreme Court of Illinois. Last verified July 20, 2026.
· Official source
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