MPEP § 1836 — MPEP § 1836
Current through: 2022-07-01

1836-Rectification of Obvious Mistakes 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

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 Manual of Patent Examining Procedure 

 Chapter 1800 

 Section 1836 
 

 
 
 
 
 
 1836 Rectification of Obvious Mistakes [R-07.2015]

 
 PCT Rule 91 

 Rectification of Obvious Mistakes in the
 International Application and Other Documents 

 
 91.1 Rectification of Obvious Mistakes

 
 (a) An obvious mistake in the international application or
 another document submitted by the applicant may be rectified in
 accordance with this Rule if the applicant so requests.
 

 (b) The rectification of a mistake shall be subject to
 authorization by the “competent authority”, that is to say:
 
 (i) in the case of a mistake in the request part of
 the international application or in a correction thereof—by the
 receiving Office;
 

 (ii) in the case of a mistake in the description,
 claims or drawings or in a correction thereof, unless the
 International Preliminary Examining Authority is competent under
 item (iii)—by the International Searching Authority;
 

 (iii) in the case of a mistake in the description,
 claims or drawings or in a correction thereof, or in an
 amendment under Article 19 
 or 34 , where a
 demand for international preliminary examination has been made
 and has not been withdrawn and the date on which international
 preliminary examination shall start in accordance with
 Rule 69.1 
 has passed—by the International Preliminary Examining
 Authority;
 

 (iv) in the case of a mistake in a document not
 referred to in items (i) to (iii) submitted to the receiving
 Office, the International Searching Authority, the International
 Preliminary Examining Authority or the International Bureau,
 other than a mistake in the abstract or in an amendment under
 Article 19 
 —by that Office, Authority or Bureau, as the case may be. 
 

 
 

 (c) The competent authority shall authorize the
 rectification under this Rule of a mistake if, and only if, it is
 obvious to the competent authority that, as at the applicable date under
 paragraph (f), something else was intended than what appears in the
 document concerned and that nothing else could have been intended than
 the proposed rectification.
 

 (d) In the case of a mistake in the description, claims or
 drawings or in a correction or amendment thereof, the competent
 authority shall, for the purposes of paragraph (c), only take into
 account the contents of the description, claims and drawings and, where
 applicable, the correction or amendment concerned.
 

 (e) In the case of a mistake in the request part of the
 international application or a correction thereof, or in a document
 referred to in paragraph (b)(iv), the competent authority shall, for the
 purposes of paragraph (c), only take into account the contents of the
 international application itself and, where applicable, the correction
 concerned, or the document referred to in paragraph (b)(iv), together
 with any other document submitted with the request, correction or
 document, as the case may be, any priority document in respect of the
 international application that is available to the authority in
 accordance with the Administrative Instructions, and any other document
 contained in the authority’s international application file at the
 applicable date under paragraph (f).
 

 (f) The applicable date for the purposes of paragraphs (c)
 and (e) shall be:
 
 (i) in the case of a mistake in a part of the
 international application as filed—the international filing
 date;
 

 (ii) in the case of a mistake in a document other
 than the international application as filed, including a mistake
 in a correction or an amendment of the international
 application—the date on which the document was submitted.
 

 
 

 (g) A mistake shall not be rectifiable under this Rule
 if:
 
 (i) the mistake lies in the omission of one or more
 entire elements of the international application referred to in
 Article
 3(2) or one or more entire sheets of the
 international application;
 

 (ii) the mistake is in the abstract;

 (iii) the mistake is in an amendment under
 Article 19 ,
 unless the International Preliminary Examining Authority is
 competent to authorize the rectification of such mistake under
 paragraph (b)(iii); or 
 

 (iv) the mistake is in a priority claim or in a
 notice correcting or adding a priority claim under
 Rule 26
 bis.1(a) , where the
 rectification of the mistake would cause a change in the
 priority date;
 
 

 

 provided that this paragraph shall not affect
 the operation of Rules 20.4 ,
 20.5 ,
 26bis and
 38.3 . 
 

 

 
 

 (h) Where the receiving Office, the International Searching
 Authority, the International Preliminary Examining Authority or the
 International Bureau discovers what appears to be a rectifiable obvious
 mistake in the international application or another document, it may
 invite the applicant to request rectification under this Rule.
 

 
 

 

 
 91.2 Requests for Rectification

 A request for rectification under Rule 91.1 
 shall be submitted to the competent authority within 26 months from the priority
 date. It shall specify the mistake to be rectified and the proposed
 rectification, and may, at the option of the applicant, contain a brief
 explanation. Rule 26.4 shall apply mutatis
 mutandis as to the manner in which the proposed rectification
 shall be indicated.
 

 

 
 91.3 Authorization and Effect of
 Rectifications
 

 

 
 (a) The competent authority shall promptly decide whether to
 authorize or refuse to authorize a rectification under Rule 91.1 and shall promptly notify the applicant
 and the International Bureau of the authorization or refusal and, in the
 case of refusal, of the reasons therefor. The International Bureau shall
 proceed as provided for in the Administrative Instructions, including, as
 required, notifying the receiving Office, the International Searching
 Authority, the International Preliminary Examining Authority and the
 designated and elected Offices of the authorization or refusal.
 

 (b) Where the rectification of an obvious mistake has been
 authorized under Rule 91.1 , the document
 concerned shall be rectified in accordance with the Administrative
 Instructions.
 

 (c) Where the rectification of an obvious mistake has been
 authorized, it shall be effective:
 
 (i) in the case of a mistake in the international
 application as filed, from the international filing date;
 

 (ii) in the case of a mistake in a document other than
 the international application as filed, including a mistake in a
 correction or an amendment of the international application, from
 the date on which that document was submitted.
 

 
 

 (d) Where the competent authority refuses to authorize a
 rectification under Rule 91.1 , the
 International Bureau shall, upon request submitted to it by the applicant
 within two months from the date of the refusal, and subject to the payment
 of a special fee whose amount shall be fixed in the Administrative
 Instructions, publish the request for rectification, the reasons for refusal
 by the authority and any further brief comments that may be submitted by the
 applicant, if possible together with the international application. A copy
 of the request, reasons and comments (if any) shall if possible be included
 in the communication under Article 20 where the
 international application is not published by virtue of Article 64(3) . 
 

 (e) The rectification of an obvious mistake need not be taken
 into account by any designated Office in which the processing or examination
 of the international application has already started prior to the date on
 which that Office is notified under Rule 91.3(a) of the
 authorization of the rectification by the competent authority.
 

 (f) A designated Office may disregard a rectification that was
 authorized under Rule 91.1 only if it
 finds that it would not have authorized the rectification under
 Rule
 91.1 if it had been the competent authority, provided
 that no designated Office shall disregard any rectification that was
 authorized under Rule 91.1 without
 giving the applicant the opportunity to make observations, within a time
 limit which shall be reasonable under the circumstances, on the Office’s
 intention to disregard the rectification.
 

 
 

 Obvious mistakes in the international application or other papers
 submitted by the applicant may generally be rectified under PCT Rule 91 , if
 the rectification is authorized, as required, within the applicable time limit. Any such
 rectification is free of charge. The omission of entire sheets of the international
 application cannot be rectified under PCT Rule 91 . Correction of such
 mistakes may only be made in accordance with PCT Rule 20.6 . Mistakes in the
 abstract, in amendments under PCT Article 19 (unless the International Preliminary
 Examining Authority is competent to authorize the rectification under PCT Rule
 91.1(b)(iii) ), or in a priority claim or in a notice correcting
 or adding a priority claim where the rectification would cause a change in the priority,
 also cannot be rectified under PCT Rule 91 . 
 

 Applicants often attempt to rely upon the priority application to
 establish a basis for obvious mistake. The priority document (application) cannot be
 used to support obvious mistake corrections to the description, claims, or drawings or
 in a correction or amendment thereof. The rectification is obvious only in the sense
 that the competent authority (i.e., the receiving Office, the International Searching
 Authority, the International Preliminary Examining Authority, or the International
 Bureau), as appropriate, would immediately realize that something else was intended
 other than what appears in the document and that nothing else could have been intended
 than what is offered as rectification. Examples of obvious mistakes that are rectifiable
 include linguistic errors, spelling errors and grammatical errors so long as the meaning
 of the disclosure does not change upon entry of the rectification. Changes to chemical
 or mathematical formulas would not generally be rectifiable unless they would be common
 knowledge to anyone. A missing chemical formula or missing line of text would not be
 considered to be an obvious mistake subject to rectification.
 

 Rectifications must be authorized:

 
 (A) by the Receiving Office if the mistake is in the request;

 (B) by the International Searching Authority if the mistake is in
 the description, claims, or drawings or in a correction thereof or in any paper
 submitted to that Authority, unless the International Preliminary Examining
 Authority is competent;
 

 (C) by the International Preliminary Examining Authority if the
 mistake is in the description, claims, or drawings or in a correction thereof,
 or in an amendment under Article 19 or
 34 , or in any paper submitted to that Authority, where a
 demand for Chapter II examination has been filed and has not been withdrawn and
 the date on which international preliminary examination shall start in
 accordance with PCT Rule 69.1 has
 passed;
 

 (D) by the International Bureau if the mistake is in any paper
 submitted to it other than the international application or amendments or
 corrections to the application.
 

 
 The request for rectification must be addressed to the authority
 competent to authorize the rectification. It must be filed within 26 months from the
 priority date.
 

 The International Searching Authority informs the applicant of the
 decision by use of Form PCT/ISA/217, while the International Preliminary Examining
 Authority informs the applicant of the decision regarding the authorization or refusal
 to authorize the rectification of obvious mistakes by use of Form PCT/IPEA/412.
 

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 1801-Basic Patent Cooperation Treaty (PCT) Principles 

 1802-PCT Definitions 

 1803-Reservations Under the PCT Taken by, and Notifications of Incompatibility Made by, the United States of America 

 1804-[Reserved] 

 1805-Where To File an International Application 

 1806-Applicants and Inventors 

 1807-Agent or Common Representative and General Power of Attorney 

 1808-Change in or Revocation of the Appointment of an Agent or a Common Representative 

 1809-Access to the USPTO patent electronic filing system 

 1810-Filing Date Requirements 

 1811-[Reserved] 

 1812-Elements of the International Application 

 1813 - 1816-[Reserved] 

 1817-PCT Member States 

 1818-[Reserved] 

 1819-Earlier Search 

 1820-Signature of Applicant 

 1821-The Request 

 1822-[Reserved] 

 1823-The Description 
 1823.01-Reference to Deposited Biological Material 

 1823.02-Filing Nucleotide and/or Amino Acid Sequence Listings in International Applications 

 
 

 1824-The Claims 

 1825-The Drawings 

 1826-The Abstract 

 1827-Fees 
 1827.01-Refund of International Application Fees 

 
 

 1828-Priority Claim and Document 
 1828.01-Restoration of the Right of Priority 

 1828.02-Continuation or Continuation-in-Part Indication in the Request 

 
 

 1829-[Reserved] 

 1830-International Application Transmittal Letter 

 1831-[Reserved] 

 1832-License Request for Foreign Filing Under the PCT 

 1833-[Reserved] 

 1834-Correspondence 
 1834.01-Filing of Correspondence by Facsimile 

 1834.02-Irregularities in the Mail or Electronic Communications Service 

 
 

 1835-[Reserved] 

 1836-Rectification of Obvious Mistakes 

 1837 - 1839-[Reserved] 

 1840-The International Searching Authority 
 1840.01-The European Patent Office as an International Searching Authority 

 1840.02-The Korean Intellectual Property Office as an International Searching Authority 

 1840.03-The Australian Patent Office (IP Australia) as an International Searching Authority 

 1840.04-[Reserved] 

 1840.05-The Israel Patent Office (ILPO) as an International Searching Authority 

 1840.06-The Japan Patent Office (JPO) as an International Searching Authority 

 1840.07-The Intellectual Property Office of Singapore (IPOS) as an International Searching Authority 

 
 

 1841-[Reserved] 

 1842-Basic Flow Under the PCT 

 1843-The International Search 
 1843.01-Prior Art for Chapter I Processing 

 1843.02-Certain Subject Matter Need Not Be Searched 

 1843.03-No Search Required if Claims Are Unclear 

 1843.04-Procedure for Claims Not Required To Be Searched and for Claims That Are Unclear 

 1843.05-Time Limit for Establishing the International Search Report and the Written Opinion of the International Searching Authority 

 
 

 1844-The International Search Report 
 1844.01-Preparing the International Search Report (Form PCT/ISA/210) 

 
 

 1845-Written Opinion of the International Searching Authority 
 1845.01-Preparing the Written Opinion of the International Searching Authority (Form PCT/ISA/237) 

 1845.02-Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority,
 or the Declaration (Form PCT/ISA/220) 

 
 

 1846 - 1847-[Reserved] 

 1848-Sequence Listings 

 1849-[Reserved] 

 1850-Unity of Invention Before the International Searching Authority 

 1851-Identification of Patent Documents 

 1852-Taking Into Account Results of Earlier Search(es) 

 1853-Amendment Under PCT Article 19 

 1854 - 1855-[Reserved] 

 1856-Supplementary International Searches 

 1857-International Publication 

 1858-[Reserved] 

 1859-Withdrawal of International Application, Designations, or Priority Claims 

 1860-International Preliminary Examination Procedure 

 1861-[Reserved] 

 1862-Agreement With the International Bureau To Serve as an International Preliminary Examining Authority 

 1863-[Reserved] 

 1864-The Demand and Preparation for Filing of Demand 
 1864.01-Amendments Filed Under PCT Article 34 

 1864.02-Applicant’s Right To File a Demand 

 1864.03-States Which May Be Elected 

 1864.04-Agent’s Right To Act 

 
 

 1865-Filing of Demand 

 1866-[Reserved] 

 1867-Preliminary Examination Fees 

 1868-Correction of Defects in the Demand 

 1869-Notification to International Bureau of Demand 

 1870-Priority Document and Translation Thereof 

 1871-Processing Amendments Filed Under Article 19 and Article 34 Prior to or at the Start of International Preliminary Examination 

 1872-Availability of the International Application File for International Preliminary Examination by the Examining Corps 

 1873-[Reserved] 

 1874-Determination if International Preliminary Examination Is Required and Possible 

 1875-Unity of Invention Before the International Preliminary Examining Authority 
 1875.01-Preparation of Invitation Concerning Unity 

 1875.02-Reply to Invitation Concerning Lack of Unity of Invention 

 
 

 1876-Notation of Errors and Informalities by the Examiner 
 1876.01-Request for Rectification and Notification of Action Thereon 

 
 

 1877-Nucleotide and/or Amino Acid Sequence Listings During the International Preliminary Examination 

 1878-Preparation of the Written Opinion of the International Preliminary Examining Authority 
 1878.01-Includes Subsections Regarding Prior Art, Novelty, Inventive Step, and Industrial Applicability for Purposes of the Written
 Opinion and the International Preliminary Examination Report 
 1878.01(a)-Prior Art for Purposes of the Written Opinion and the International Preliminary Examination Report 
 1878.01(a)(1)-Novelty for Purposes of the Written Opinion and the International Preliminary Examination Report 

 1878.01(a)(2)-Inventive Step for Purposes of the Written Opinion and the International Preliminary Examination Report 

 1878.01(a)(3)-Industrial Applicability for Purposes of the Written Opinion and the International Preliminary Examination Report 

 
 

 
 

 1878.02-Reply to the Written Opinion of the ISA or IPEA 

 
 

 1879-Preparation of the International Preliminary Examination Report 
 1879.01-Time Limit for Preparing Report 

 1879.02-Transmittal of the International Preliminary Examination Report and Related Documents 

 1879.03-Translations 

 1879.04-Confidential Nature of the Report 

 
 

 1880-Withdrawal of Demand or Election 

 1881-Receipt of Notice of Election and Preliminary Examination Report by the United States Patent and Trademark Office 

 1882 - 1892-[Reserved] 

 1893-National Stage (U.S. National Application Filed Under 35 U.S.C. 371) 
 1893.01-Commencement and Entry 
 1893.01(a)-Entry via the U.S. Designated or Elected Office 
 1893.01(a)(1)-Submissions Required by 30 Months from the Priority Date 

 1893.01(a)(2)-Article 19 Amendment (Filed With the International Bureau) 

 1893.01(a)(3)-Article 34 Amendments (Filed with the International Preliminary Examining Authority) 

 1893.01(a)(4)-Claim Amendment (Filed With the U.S. Designated or Elected Office) 

 
 

 1893.01(b)-Applicant for a U.S. National Stage Application 

 1893.01(c)-Fees 

 1893.01(d)-Translation 

 1893.01(e)-Inventor’s Oath or Declaration 

 
 

 1893.02-Abandonment 

 1893.03-Prosecution of U.S. National Stage Applications Before the Examiner 
 1893.03(a)-How To Identify That an Application Is a U.S. National Stage Application 

 1893.03(b)-The Filing Date of a U.S. National Stage Application 

 1893.03(c)-The Priority Date, Priority Claim, and Priority Papers for a U.S. National Stage Application 

 1893.03(d)-Unity of Invention 

 1893.03(e)-Documents Received from the International Bureau and Placed in a U.S. National Stage Application File 
 1893.03(e)(1)-Title of the Invention 

 
 

 1893.03(f)-Drawings and PCT Rule 11 

 1893.03(g)-Information Disclosure Statement in a National Stage Application 

 
 

 
 

 1894-[Reserved] 

 1895-A Continuation, Divisional, or Continuation- in- Part Application of a PCT Application Designating the United States 
 1895.01-Handling of and Considerations in the Handling of Continuations, Divisions, and Continuations-In-Part of PCT Applications 

 
 

 1896-The Differences Between a National Application Filed Under 35 U.S.C. 111(a) and a National Stage Application Submitted Under
 35 U.S.C. 371 

 

 

 
 

 
 
 

 
 

 

 
 
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 Last Modified: 
 
 03/09/2026 20:50:37