MPEP § 1834.02 — Irregularities in the Mail or Electronic Communications Service (Annotated Rules)

§1834.02 Irregularities in the Mail or Electronic Communications Service

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

This page consolidates and annotates all enforceable requirements under MPEP § 1834.02, 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.

Irregularities in the Mail or Electronic Communications Service

This section addresses Irregularities in the Mail or Electronic Communications Service. Contains: 4 requirements, 1 permission, and 4 other statements.

Key Rules

Topic

Period Computation Rules

4 rules
MPEP GuidanceRequiredAlways
[mpep-1834-02-4ad6a3ba361af87eb8bf4119]
Evidence of Mailing Must Be Submitted Within One Month
Note:
The interested party must submit evidence of mailing and, if the document is lost, a substitute document along with identity evidence within one month after noticing the delay or loss, but no later than six months from the time limit expiration.

(c) In the cases provided for in paragraph (b), evidence of mailing within the prescribed time limit, and, where the document or letter was lost, the substitute document or letter as well as the evidence concerning its identity with the document or letter lost shall be submitted within one month after the date on which the interested party noticed or with due diligence should have noticed the delay or the loss, and in no case later than six months after the expiration of the time limit applicable in the given case.

Jump to MPEP SourcePeriod Computation RulesSix Month Statutory PeriodStatutory Period Computation (37 CFR 1.134)
MPEP GuidanceRequiredAlways
[mpep-1834-02-213246d56f1e9141981559eb]
Registered Mail Required for Timely Filing
Note:
Documents must be mailed by registered air mail or surface mail within two days of arrival, to meet filing deadlines.

Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c)). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.

Jump to MPEP SourcePeriod Computation RulesPatent Cooperation TreatyReceiving Office (RO/US)
MPEP GuidanceInformativeAlways
[mpep-1834-02-e841e94b0a40bbc6fa2b56d8]
Excuse for Late Mailed Documents
Note:
Allows up to six months late filing if document was mailed at least five days before the deadline and by registered mail.

Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c)). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.

Jump to MPEP SourcePeriod Computation RulesSix Month Statutory PeriodPCT International Application Filing
MPEP GuidanceRequiredAlways
[mpep-1834-02-fa2653a1aa2a0843195d2b08]
Mailing Must Be Registered Air or Surface Within Two Days
Note:
The mailing must be by registered air mail or surface mail within two days of arrival to qualify for late filing exceptions.

Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c)). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.

Jump to MPEP SourcePeriod Computation RulesReceiving Office (RO/US)Six Month Statutory Period
Topic

Patent Cooperation Treaty

3 rules
MPEP GuidanceInformativeAlways
[mpep-1834-02-ef6ed72566639028049cc3d8]
PCT Late Mail Excuse for Lost Documents
Note:
Excuses failure to meet time limits due to lost or delayed mail, requiring proof of mailing at least five days before the deadline and using registered airmail or surface mail.

Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c)). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.

Jump to MPEP SourcePatent Cooperation TreatyReceiving Office (RO/US)Period Computation Rules
MPEP GuidanceRequiredAlways
[mpep-1834-02-340e58970765200d18ee3df4]
Substitute Document Required for Late Filing
Note:
A substitute document must be filed promptly when evidence proves a letter was mailed at least five days before the time limit, using registered mail.

Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c)). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.

Jump to MPEP SourcePatent Cooperation TreatyReceiving Office (RO/US)Period Computation Rules
MPEP GuidanceInformativeAlways
[mpep-1834-02-aca675d22eeb54de3b9325a8]
PCT Periods Expire on Non-Working Days
Note:
Guidance for when periods under PCT rules expire on non-working days.

See PCT Rule 80.5 for guidance on periods which expire on a non-working day.

Jump to MPEP SourcePatent Cooperation Treaty
Topic

Extension Limits

2 rules
StatutoryPermittedAlways
[mpep-1834-02-ba81c4b0d83ca5d2b9abc88e]
Delay Excused for Widespread Electronic Communication Outages
Note:
A delay in meeting time limits may be excused if an outage of electronic communications services affected a widespread area, was unexpected, and no alternative means of communication was available.

Special provisions apply to excuse delays in meeting time limits fixed in the PCT Regulations, and to extend time limits due to a general disruption experienced by an office or authority, caused by war, revolution, civil disorder, strike, natural calamity, epidemic, a general unavailability of electronic communications services or other like reasons. For example, a delay in meeting a time limit may be excused where the interested party establishes that an outage of electronic communications services affected a widespread geographical area, was unexpected or unforeseen, and that no alternative means of communication was available. See PCT Rule 82quater and PCT Administrative Instruction Section 111 for details.

Jump to MPEP SourceExtension LimitsPeriod for Reply (37 CFR 1.134)Extension of Time (37 CFR 1.136)
StatutoryInformativeAlways
[mpep-1834-02-2ceae95802ce163a2a7ec247]
Extension of Time for PCT Due to Disruption
Note:
Allows delays in meeting time limits due to general disruptions like war or natural disasters.

Special provisions apply to excuse delays in meeting time limits fixed in the PCT Regulations, and to extend time limits due to a general disruption experienced by an office or authority, caused by war, revolution, civil disorder, strike, natural calamity, epidemic, a general unavailability of electronic communications services or other like reasons. For example, a delay in meeting a time limit may be excused where the interested party establishes that an outage of electronic communications services affected a widespread geographical area, was unexpected or unforeseen, and that no alternative means of communication was available. See PCT Rule 82quater and PCT Administrative Instruction Section 111 for details.

Jump to MPEP SourceExtension LimitsExtension of Time (37 CFR 1.136)Period for Reply (37 CFR 1.134)
Topic

Extension of Time (37 CFR 1.136)

1 rules
StatutoryInformativeAlways
[mpep-1834-02-cbdf6dbba2ed6f3292d6dc74]
Extension of Time Limits Due to Disruptions
Note:
Allows delays in meeting PCT time limits due to general disruptions like war or natural disasters.

Special provisions apply to excuse delays in meeting time limits fixed in the PCT Regulations, and to extend time limits due to a general disruption experienced by an office or authority, caused by war, revolution, civil disorder, strike, natural calamity, epidemic, a general unavailability of electronic communications services or other like reasons. For example, a delay in meeting a time limit may be excused where the interested party establishes that an outage of electronic communications services affected a widespread geographical area, was unexpected or unforeseen, and that no alternative means of communication was available. See PCT Rule 82quater and PCT Administrative Instruction Section 111 for details.

Jump to MPEP SourceExtension of Time (37 CFR 1.136)Extension LimitsPeriod for Reply (37 CFR 1.134)
Topic

Patent Term Expiration

1 rules
MPEP GuidancePermittedAlways
[mpep-1834-02-b88feed87cd0ff3286d89f96]
Airmail Must Be Used for Timely Mailing
Note:
An interested party must use airmail to mail documents or letters five days before the expiration of the time limit, unless surface mail typically arrives within two days.

(a) Any interested party may offer evidence that he has mailed the document or letter five days prior to the expiration of the time limit. Except in cases where surface mail normally arrives at its destination within two days of mailing, or where no airmail service is available, such evidence may be offered only if the mailing was by airmail. In any case, evidence may be offered only if the mailing was by mail registered by the postal authorities.

Jump to MPEP SourcePatent Term ExpirationPatent TermPTAB Contested Case Procedures
Topic

Practitioner Recognition and Conduct

1 rules
MPEP GuidancePermittedAlways
[mpep-1834-02-1254e9e138662f4c8b0d2505]
Airmail and Registered Mail Required for Evidence
Note:
Evidence of mailing can only be offered if the document was sent by airmail or registered mail according to postal authorities.

(a) Any interested party may offer evidence that he has mailed the document or letter five days prior to the expiration of the time limit. Except in cases where surface mail normally arrives at its destination within two days of mailing, or where no airmail service is available, such evidence may be offered only if the mailing was by airmail. In any case, evidence may be offered only if the mailing was by mail registered by the postal authorities.

Jump to MPEP SourcePractitioner Recognition and ConductPatent Term ExpirationPatent Term
Topic

PTAB Contested Case Procedures

1 rules
MPEP GuidanceRequiredAlways
[mpep-1834-02-8df1baf07e99f440c9f5487c]
Substitution for Lost Document Allowed
Note:
If a document is lost in the mail, a new identical copy can be provided upon proof to the national Office or intergovernmental organization.

(b) If the mailing, in accordance with paragraph (a), of a document or letter is proven to the satisfaction of the national Office or intergovernmental organization which is the addressee, delay in arrival shall be excused, or, if the document or letter is lost in the mail, substitution for it of a new copy shall be permitted, provided that the interested party proves to the satisfaction of the said Office or organization that the document or letter offered in substitution is identical with the document or letter lost.

Jump to MPEP SourcePTAB Contested Case Procedures
Topic

Receiving Office (RO/US)

1 rules
MPEP GuidanceRequiredAlways
[mpep-1834-02-b2ccd7575e62bb5675c4bf14]
Requirement for Early Mailing to Avoid Delay or Loss
Note:
Documents must be mailed at least five days before the deadline by registered air or surface mail to avoid delay or loss penalties.

Delay or loss in the mail shall be excused when it is proven to the satisfaction of the receiving Office that the concerned letter or document was mailed at least five days before the expiration of the time limit. The mailing must have been by registered air mail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail (PCT Rule 82.1(a) to (c)). PCT Rule 82 contains detailed provisions governing the situation where a letter arrives late or gets lost due to irregularities in the mail service, for example, because the mail service was interrupted due to a strike. The provisions operate to excuse failure to meet a time limit for filing a document for up to six months after the expiration of the time limit concerned, provided that the document was mailed at least five days before the expiration of the time limit. In order to take advantage of these provisions, the mailing must have been by registered airmail or, where surface mail would normally arrive at the destination concerned within two days of mailing, by registered surface mail. Evidence is required to satisfy the Office, and a substitute document must be filed promptly—see PCT Rule 82.1(b) and (c) for details.

Jump to MPEP SourceReceiving Office (RO/US)Period Computation RulesPCT International Application Filing

Citations

Primary topicCitation
Patent Cooperation TreatyPCT Rule 80.5
Patent Cooperation Treaty
Period Computation Rules
Receiving Office (RO/US)
PCT Rule 82.1(b)
Extension Limits
Extension of Time (37 CFR 1.136)
PCT Rule 82quater

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