MPEP § 2211 — Time for Requesting Ex Parte Reexamination under 35 U.S.C. 302 (Annotated Rules)

§2211 Time for Requesting Ex Parte Reexamination under 35 U.S.C. 302

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 2211, including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Time for Requesting Ex Parte Reexamination under 35 U.S.C. 302

This section addresses Time for Requesting Ex Parte Reexamination under 35 U.S.C. 302. Primary authority: 35 U.S.C. 154, 35 U.S.C. 156, and 37 CFR 1.510(a). Contains: 1 prohibition, 1 guidance statement, 3 permissions, and 2 other statements.

Key Rules

Topic

Ex Parte Reexamination Request

4 rules
StatutoryPermittedAlways
[mpep-2211-a54408acde5feab78fa79c2b]
Any Person May File Ex Parte Reexamination at Any Time During Patent Enforceability
Note:
Under 37 CFR 1.510(a), any individual can request ex parte reexamination of a patent at any time while the patent is enforceable, even if the statute of limitations has expired.

Under 37 CFR 1.510(a), any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination. This period was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced. See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The period of enforceability is generally determined by adding 6 years to the date on which the patent expires but the period may be extended if there is pending litigation. Specifically, if litigation is instituted within the period of the statute of limitations, requests for reexamination may be filed after the statute of limitations has expired, as long as the patent is still enforceable.

Jump to MPEP Source · 37 CFR 1.510(a)Ex Parte Reexamination RequestEx Parte ReexaminationLate Payment and Reinstatement
StatutoryProhibitedAlways
[mpep-2211-d2282ad09c5753837c027f0d]
Period for Ex Parte Reexamination Set by Rule
Note:
The Office sets the period for filing an ex parte reexamination request, considering Congress did not intend to use Office resources on unenforceable patents.

Under 37 CFR 1.510(a), any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination. This period was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced. See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The period of enforceability is generally determined by adding 6 years to the date on which the patent expires but the period may be extended if there is pending litigation. Specifically, if litigation is instituted within the period of the statute of limitations, requests for reexamination may be filed after the statute of limitations has expired, as long as the patent is still enforceable.

Jump to MPEP Source · 37 CFR 1.510(a)Ex Parte Reexamination RequestEx Parte ReexaminationLate Payment and Reinstatement
StatutoryInformativeAlways
[mpep-2211-54f6fa75de6f8bae0ea7ede7]
Request for Ex Parte Reexamination Allowed During Patent Enforceability Period
Note:
Any person may file a request for ex parte reexamination at any time during the patent's enforceability period, which is generally 6 years from expiration and can be extended if there is pending litigation.

Under 37 CFR 1.510(a), any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination. This period was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced. See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The period of enforceability is generally determined by adding 6 years to the date on which the patent expires but the period may be extended if there is pending litigation. Specifically, if litigation is instituted within the period of the statute of limitations, requests for reexamination may be filed after the statute of limitations has expired, as long as the patent is still enforceable.

Jump to MPEP Source · 37 CFR 1.510(a)Ex Parte Reexamination RequestEx Parte ReexaminationLate Payment and Reinstatement
StatutoryPermittedAlways
[mpep-2211-6f777d3de51521bac2fc2037]
Period of Enforceability for Ex Parte Reexamination Requests
Note:
The period to request ex parte reexamination is generally 6 years after the patent expires, but can be extended if there is pending litigation.

Under 37 CFR 1.510(a), any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination. This period was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced. See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The period of enforceability is generally determined by adding 6 years to the date on which the patent expires but the period may be extended if there is pending litigation. Specifically, if litigation is instituted within the period of the statute of limitations, requests for reexamination may be filed after the statute of limitations has expired, as long as the patent is still enforceable.

Jump to MPEP Source · 37 CFR 1.510(a)Ex Parte Reexamination RequestEx Parte ReexaminationLate Payment and Reinstatement
Topic

Determining Expiration Date

2 rules
StatutoryInformativeAlways
[mpep-2211-1630e427d9e31a0328d0c311]
Determining Patent Expiration Date
Note:
This rule outlines the factors to consider when determining a utility patent's expiration date, including term, maintenance fees, disclaimers, and extensions or adjustments.

The patent expiration date for a utility patent, for example, is determined by taking into account the term of the patent, whether maintenance fees have been paid for the patent, whether any disclaimer was filed as to the patent to shorten its term, any patent term extensions or adjustments for delays within the Office under 35 U.S.C. 154 (see MPEP § 2710, et seq.), and any patent term extensions available under 35 U.S.C. 156 for premarket regulatory review (see MPEP § 2750 et seq.). Any other relevant information should also be taken into account.

Jump to MPEP SourceDetermining Expiration DatePatent Term ExpirationPatent Term
StatutoryRecommendedAlways
[mpep-2211-57f7d21018cafbc98f1a5b87]
Term Expiration Determined by Multiple Factors
Note:
The expiration date of a utility patent is determined based on the term, payment of maintenance fees, any disclaimers filed to shorten the term, and extensions or adjustments for delays within the Office.

The patent expiration date for a utility patent, for example, is determined by taking into account the term of the patent, whether maintenance fees have been paid for the patent, whether any disclaimer was filed as to the patent to shorten its term, any patent term extensions or adjustments for delays within the Office under 35 U.S.C. 154 (see MPEP § 2710, et seq.), and any patent term extensions available under 35 U.S.C. 156 for premarket regulatory review (see MPEP § 2750 et seq.). Any other relevant information should also be taken into account.

Jump to MPEP SourceDetermining Expiration DatePatent Term ExpirationPatent Term
Topic

Late Payment and Reinstatement

1 rules
StatutoryPermittedAlways
[mpep-2211-0b0a5456d02d874f4ae374ed]
Request for Reexamination Allowed After Limitations If Litigation Instituted
Note:
A request for ex parte reexamination can be filed after the statute of limitations has expired if litigation is instituted within the patent's enforceability period.

Under 37 CFR 1.510(a), any person may, at any time during the period of enforceability of a patent, file a request for ex parte reexamination. This period was set by rule, since the Office considered that Congress could not have intended expending Office resources on deciding patent validity questions in patents which cannot be enforced. See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985). The period of enforceability is generally determined by adding 6 years to the date on which the patent expires but the period may be extended if there is pending litigation. Specifically, if litigation is instituted within the period of the statute of limitations, requests for reexamination may be filed after the statute of limitations has expired, as long as the patent is still enforceable.

Jump to MPEP Source · 37 CFR 1.510(a)Late Payment and ReinstatementEx Parte Reexamination RequestEx Parte Reexamination

Citations

Primary topicCitation
Determining Expiration Date35 U.S.C. § 154
Determining Expiration Date35 U.S.C. § 156
Ex Parte Reexamination Request
Late Payment and Reinstatement
37 CFR § 1.510(a)
Determining Expiration DateMPEP § 2710
Determining Expiration DateMPEP § 2750
Ex Parte Reexamination Request
Late Payment and Reinstatement
See Patlex Corp. v. Mossinghoff, 758 F.2d 594, 225 USPQ 243, 249 (Fed. Cir. 1985)

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2025-12-31