MPEP § 1845 — Written Opinion of the International Searching Authority (Annotated Rules)

§1845 Written Opinion of the International Searching Authority

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

This page consolidates and annotates all enforceable requirements under MPEP § 1845, 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.

Written Opinion of the International Searching Authority

This section addresses Written Opinion of the International Searching Authority. Contains: 6 requirements, 2 permissions, and 2 other statements.

Key Rules

Topic

Article 34 Amendments

4 rules
StatutoryPermittedAlways
[mpep-1845-ecff693f1adb8f991aec98e0]
Documents and Arguments for International Preliminary Examination
Note:
The international search report and written opinion provide necessary information for the International Preliminary Examining Authority and designated Offices during the national phase examination.

The examiner is required, in most instances, to establish a written opinion on novelty, inventive step, and industrial applicability of the claimed invention at the same time he/she establishes the international search report. The international search report and written opinion together serve to inform the International Preliminary Examining Authority of the documents and arguments necessary to complete the relevant assessments if international preliminary examination is demanded, and to inform the designated Offices of information that may be relevant to examination in the national phase. (The written opinion is transmitted to the designated offices in the form of an international preliminary report on patentability if no international preliminary examination report is established under Chapter II of the PCT). A written opinion of the International Searching Authority is not required in the limited instance where a demand for international preliminary examination and required fees (PCT Rule 69.1(a)) have been filed with the United States International Preliminary Examining Authority and the examiner considers all the conditions of PCT Article 34(2)(c)(i) to (iii) to be fulfilled. In this limited instance, a positive international preliminary examination report may be issued. See PCT Rule 69.1(b-bis)).

Jump to MPEP SourceArticle 34 AmendmentsInternational Preliminary Examining Authority (IPEA)International Searching Authority (ISA)
StatutoryInformativeAlways
[mpep-1845-a0ac45c1c81bdbf1cdcfc147]
International Preliminary Report on Patentability Transmitted
Note:
The written opinion is transmitted to designated offices as an international preliminary report on patentability unless international preliminary examination is demanded.

The examiner is required, in most instances, to establish a written opinion on novelty, inventive step, and industrial applicability of the claimed invention at the same time he/she establishes the international search report. The international search report and written opinion together serve to inform the International Preliminary Examining Authority of the documents and arguments necessary to complete the relevant assessments if international preliminary examination is demanded, and to inform the designated Offices of information that may be relevant to examination in the national phase. (The written opinion is transmitted to the designated offices in the form of an international preliminary report on patentability if no international preliminary examination report is established under Chapter II of the PCT). A written opinion of the International Searching Authority is not required in the limited instance where a demand for international preliminary examination and required fees (PCT Rule 69.1(a)) have been filed with the United States International Preliminary Examining Authority and the examiner considers all the conditions of PCT Article 34(2)(c)(i) to (iii) to be fulfilled. In this limited instance, a positive international preliminary examination report may be issued. See PCT Rule 69.1(b-bis)).

Jump to MPEP SourceArticle 34 AmendmentsDemand for Preliminary ExaminationInternational Preliminary Report on Patentability
StatutoryRequiredAlways
[mpep-1845-d1e603e041175b64f3833f22]
Written Opinion Not Needed for U.S. Examiner
Note:
A written opinion from the International Searching Authority is not required when a demand for international preliminary examination and fees are filed with the U.S. examiner, and all PCT Article 34(2)(c) conditions are met.

The examiner is required, in most instances, to establish a written opinion on novelty, inventive step, and industrial applicability of the claimed invention at the same time he/she establishes the international search report. The international search report and written opinion together serve to inform the International Preliminary Examining Authority of the documents and arguments necessary to complete the relevant assessments if international preliminary examination is demanded, and to inform the designated Offices of information that may be relevant to examination in the national phase. (The written opinion is transmitted to the designated offices in the form of an international preliminary report on patentability if no international preliminary examination report is established under Chapter II of the PCT). A written opinion of the International Searching Authority is not required in the limited instance where a demand for international preliminary examination and required fees (PCT Rule 69.1(a)) have been filed with the United States International Preliminary Examining Authority and the examiner considers all the conditions of PCT Article 34(2)(c)(i) to (iii) to be fulfilled. In this limited instance, a positive international preliminary examination report may be issued. See PCT Rule 69.1(b-bis)).

Jump to MPEP SourceArticle 34 AmendmentsDemand for Preliminary ExaminationInternational Preliminary Examining Authority (IPEA)
StatutoryPermittedAlways
[mpep-1845-310e0e600e9708fa62034eff]
Positive International Preliminary Examination Report Permitted
Note:
A positive international preliminary examination report may be issued when the conditions for Article 34(2)(c) of the PCT are met.

The examiner is required, in most instances, to establish a written opinion on novelty, inventive step, and industrial applicability of the claimed invention at the same time he/she establishes the international search report. The international search report and written opinion together serve to inform the International Preliminary Examining Authority of the documents and arguments necessary to complete the relevant assessments if international preliminary examination is demanded, and to inform the designated Offices of information that may be relevant to examination in the national phase. (The written opinion is transmitted to the designated offices in the form of an international preliminary report on patentability if no international preliminary examination report is established under Chapter II of the PCT). A written opinion of the International Searching Authority is not required in the limited instance where a demand for international preliminary examination and required fees (PCT Rule 69.1(a)) have been filed with the United States International Preliminary Examining Authority and the examiner considers all the conditions of PCT Article 34(2)(c)(i) to (iii) to be fulfilled. In this limited instance, a positive international preliminary examination report may be issued. See PCT Rule 69.1(b-bis)).

Jump to MPEP SourceArticle 34 AmendmentsInternational Preliminary Examination (Chapter II)National Stage Examination
Topic

Patent Cooperation Treaty

3 rules
StatutoryInformativeAlways
[mpep-1845-6673aa24f9d69bb80c290072]
Requirement for International Preliminary Examination
Note:
The examiner must establish a written opinion on novelty, inventive step, and industrial applicability if international preliminary examination is demanded.

The examiner is required, in most instances, to establish a written opinion on novelty, inventive step, and industrial applicability of the claimed invention at the same time he/she establishes the international search report. The international search report and written opinion together serve to inform the International Preliminary Examining Authority of the documents and arguments necessary to complete the relevant assessments if international preliminary examination is demanded, and to inform the designated Offices of information that may be relevant to examination in the national phase. (The written opinion is transmitted to the designated offices in the form of an international preliminary report on patentability if no international preliminary examination report is established under Chapter II of the PCT). A written opinion of the International Searching Authority is not required in the limited instance where a demand for international preliminary examination and required fees (PCT Rule 69.1(a)) have been filed with the United States International Preliminary Examining Authority and the examiner considers all the conditions of PCT Article 34(2)(c)(i) to (iii) to be fulfilled. In this limited instance, a positive international preliminary examination report may be issued. See PCT Rule 69.1(b-bis)).

Jump to MPEP SourcePatent Cooperation TreatyArticle 34 AmendmentsDemand for Preliminary Examination
StatutoryRequiredAlways
[mpep-1845-edc09d92a94563aab58053a6]
Defects Must Be Notified to Applicant
Note:
The applicant must be informed of the defects found in their application, along with reasons for the examiner's opinion and an invitation for a written reply with necessary amendments.

The applicant must be notified in the written opinion of the defects found in the application. The examiner is further required to fully state the reasons for his/her opinion (PCT Rules 66.1bis and 66.2(b)) and invite a written reply, with amendments where appropriate (PCT Rule 66.2(c)).

Jump to MPEP SourcePatent Cooperation Treaty
StatutoryRequiredAlways
[mpep-1845-0707641bbb9122416978a9ac]
Examiner Must State Reasons and Invite Reply
Note:
The examiner must provide full reasons for their opinion on the application and invite a written reply with necessary amendments.

The applicant must be notified in the written opinion of the defects found in the application. The examiner is further required to fully state the reasons for his/her opinion (PCT Rules 66.1bis and 66.2(b)) and invite a written reply, with amendments where appropriate (PCT Rule 66.2(c)).

Jump to MPEP SourcePatent Cooperation Treaty
Topic

International Searching Authority (ISA)

2 rules
StatutoryRequiredAlways
[mpep-1845-025a64403364189c7e1e3cbc]
ISA Must Establish Written Opinion on Novelty and Compliance
Note:
The International Searching Authority must simultaneously establish a written opinion on the novelty, inventive step, industrial applicability of the claimed invention, and compliance with treaty requirements.
(a) Subject to Rule 69.1(b-bis), the International Searching Authority shall, at the same time as it establishes the international search report or the declaration referred to in Article 17(2)(a), establish a written opinion as to: The written opinion shall also be accompanied by such other observations as these Regulations provide for.
  • (i) whether the claimed invention appears to be novel, to involve an inventive step (to be non-obvious), and to be industrially applicable;
  • (ii) whether the international application complies with the requirements of the Treaty and these Regulations in so far as checked by the International Searching Authority.
Jump to MPEP SourceInternational Searching Authority (ISA)International Search ReportWritten Opinion of ISA
StatutoryRequiredAlways
[mpep-1845-5c774af3cbb431e06f9a1018]
Requirement for Written Opinion on Novelty and Inventive Step
Note:
The examiner must provide a written opinion on the novelty, inventive step, and industrial applicability of the claimed invention along with the international search report.

The examiner is required, in most instances, to establish a written opinion on novelty, inventive step, and industrial applicability of the claimed invention at the same time he/she establishes the international search report. The international search report and written opinion together serve to inform the International Preliminary Examining Authority of the documents and arguments necessary to complete the relevant assessments if international preliminary examination is demanded, and to inform the designated Offices of information that may be relevant to examination in the national phase. (The written opinion is transmitted to the designated offices in the form of an international preliminary report on patentability if no international preliminary examination report is established under Chapter II of the PCT). A written opinion of the International Searching Authority is not required in the limited instance where a demand for international preliminary examination and required fees (PCT Rule 69.1(a)) have been filed with the United States International Preliminary Examining Authority and the examiner considers all the conditions of PCT Article 34(2)(c)(i) to (iii) to be fulfilled. In this limited instance, a positive international preliminary examination report may be issued. See PCT Rule 69.1(b-bis)).

Jump to MPEP SourceInternational Searching Authority (ISA)International Search ReportWritten Opinion of ISA
Topic

Patent Term Expiration

1 rules
StatutoryRequiredAlways
[mpep-1845-c3f07a303cd47e9271f215a6]
Notification of Written Opinion as International Preliminary Exam Authority
Note:
The written opinion will notify the applicant that if an international preliminary examination is requested, it will be considered the opinion of the International Preliminary Examining Authority and require a reply with amendments before the deadline.

(c) The written opinion shall contain a notification informing the applicant that, if a demand for international preliminary examination is made, the written opinion shall, under Rule 66.1bis(a) but subject to Rule 66.1bis(b), be considered to be a written opinion of the International Preliminary Examining Authority for the purposes of Rule 66.2(a), in which case the applicant is invited to submit to that Authority, before the expiration of the time limit under Rule 54 bis.1(a), a written reply together, where appropriate, with amendments.

Jump to MPEP SourcePatent Term ExpirationPatent TermPeriod for Reply (37 CFR 1.134)

Citations

Primary topicCitation
Article 34 Amendments
International Searching Authority (ISA)
Patent Cooperation Treaty
PCT Article 34(2)(c)(i)
Patent Cooperation TreatyPCT Rule 66.2(c)
Article 34 Amendments
International Searching Authority (ISA)
Patent Cooperation Treaty
PCT Rule 69.1

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