An undertaking together with any affidavit required by this article shall be filed with the clerk of the court in which the action is triable, or, upon an appeal, in the office where the judgment or order of the court of original instance is entered, and a copy shall be served upon the adverse party. The undertaking is effective when so served and filed.
§ 2505.Filing of undertaking; service upon adverse party; time when effective
Article 25. Undertakings · Last amended 1965 · Last verified July 21, 2026
In one sentenceCPLR 2505 requires an undertaking, along with any required affidavit, to be filed with the clerk of the court where the action is triable, or the appropriate office on appeal, and served on the adverse party, making the undertaking effective only once both steps are complete.
Full Text of CPLR 2505
Plain-English Summary
An undertaking does not do anything for anyone until it clears two administrative steps. CPLR 2505 requires the undertaking and any affidavit this article requires to be filed with the clerk of the court where the action is triable — or, if the undertaking supports an appeal, in the office where the judgment or order of the original court was entered. A copy must also be served on the adverse party.
The undertaking becomes effective only when both the filing and the service have happened. That two-step trigger matters when timing is tight — a party relying on an undertaking to stay a judgment or support an injunction cannot treat it as operative before it has been filed and served.
Frequently Asked Questions
Where do you file an undertaking in a New York case?
CPLR 2505 requires filing with the clerk of the court where the action is triable, or, if the undertaking is for an appeal, in the office where the judgment or order of the court of original instance was entered.
Does the other side get a copy of the undertaking?
Yes. CPLR 2505 requires a copy of the undertaking to be served on the adverse party.
When does an undertaking become effective in New York?
It becomes effective when it has been both served on the adverse party and filed with the appropriate clerk or office, under CPLR 2505.
Where do you file an undertaking supporting an appeal?
In the office where the judgment or order of the court of original instance is entered, rather than with the appellate court itself.
Is an undertaking effective as soon as it is signed by the surety?
No. CPLR 2505 makes it effective only once it has been filed and served, not merely executed.
Advisory Committee Notes
This section replaces part of the second sentence of subd 3 of CPA § 150-a, the last sentence of § 565, § 567, part of the first sentence of § 864, the first sentence and part of the second sentence of § 955, and part of CPA § 1524 and RCP 26. It describes the usual procedure for filing and giving notice of undertakings implicit throughout the CPA.
The provision in former § 567 that upon an appeal to the court of appeals, the undertaking must be filed with the clerk of the court where the original judgment or order was entered is made generally applicable to undertakings on appeal. This will conform with CPLR § 5519(c), which generally empowers the court of original instance to act in granting, limiting, vacating or modifying a stay where an appeal is taken. The first clause of former § 567 is therefore omitted since no distinction in the place of filing on the basis of whether the appeal is taken to the Court on Appeals or to some other court seems warranted.
The provision of the last sentence of former § 565, that the notice must show where the undertaking is filed, is omitted since the new section makes it clear where that place is. The provision therein that a copy of the undertaking must be served on the attorney for the adverse party is made unnecessary by the general provision of CPLR rule 2103(b) that papers required to be served upon a party shall be served upon his attorney.
The undertaking will serve its purpose—as, for example, to stay enforcement—when it is served, unless otherwise provided by the order pursuant to which it is given.
RCP 26 is omitted. There is no reason to expressly impose upon the attorney the duty of filing the undertaking. The second sentence of former rule 26 is unnecessary, since the court always has discretion to vacate the proceedings if the undertaking has not been properly filed. To the extent that former rule 26 implied that the discretion of the court upon failure to properly file the undertaking is limited to vacatur, it was misleading. The court should have discretion to take any necessary action, which may include permitting the party in default to cure an improper filing where no one has been prejudiced.
In addition to the filing required by this section, undertakings where real property is offered as security should be filed in the office of the clerk or register of the county where the real property is located. See CPLR § 2303(c). Where security is required to protect a sheriff, the particular provisions providing for such security will require that a copy be served on the sheriff. Cf. CPLR § 2506(a).
Amendment History
Add, L 1962, ch 308, § 1; amd, L 1965, ch 773, § 7, eff Sept 1, 1965.
Source & verification. Provision text, History, and Advisory
Committee Notes are reproduced verbatim from the Consolidated Laws of New York.
Last verified July 21, 2026.
· Official source
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