Written Communications Procedures

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This section provides guidance on the procedures for written communications with the Commissioner of Patents and the Patent Office.

1.0. General requirements for submission of written communications

All written communications must be addressed to the attention of the Commissioner of Patents (section 6 of the Patent Rules).

A person doing business with the Patent Office via written communication must always provide their postal address. (section 7 of the Patent Rules)

Each piece of written communication must pertain to a single patent application or patent and at a minimum, it must identify the application/patent number and the applicant/patentee name(s). (sections 8 and 9 of the Patent Rules)

1.1. Exception for communications relating to more than one application or patent

Written communications are permitted to relate to more than a single patent application or patent if the communication pertains to the following:

  1. changes in name and address,
  2. transfers,
  3. requests to register documents,
  4. payment of maintenance fees,
  5. appointments or revocations of agent, or
  6. correction of an error, if the error is the same in each application or patent.

(subsection 8(2) of the Patent Rules)

1.2. Exception identifying the patent application number

If the patent application number is not known (ex. in cases where the national phase of a Patent Cooperation Treaty (PCT) application has not yet entered the national phase or an application number has not yet been assigned), then sufficient information must be given in order to identify that application. The Patent Office will do its best to identify the patent application with the information provided. Please note however that the Patent Office databases have limited search functions and we encourage clients to provide as much information as possible when the application number is not known. (subsection 9(1) of the Patent Rules)

1.3. Who can communicate with the Office

There are specific requirements in the Patent Rules regarding who can communicate with the Office with respect to patent applications and patents for the purposes of various actions. Please see the section on Representation for more information.

2.0 Physical Delivery of Written Communications

Written communications may be physically delivered to the Patent Office by mail, in person, or to a designated establishment only as outlined in the section below. (section 10 of the Patent Rules)

For information on the date of receipt accorded to documents, information or fees, please see the Time document.

2.1 Regular Mail or In Person

Written communications addressed to the Commissioner of Patent can be sent by mail or delivered in-person to the Patent Office during ordinary business hours at the following address:

Canadian Intellectual Property Office
Place du Portage I
50 Victoria Street, Room C-114
Gatineau QC K1A 0C9

Please be advised that once communications are received by CIPO they cannot be returned to the sender, even if the sender states that the communication was sent by mistake. When submitting a fee, the Office recommends that the Fee form should be submitted as a covering document and should be the only document submitted to CIPO that contains financial information, such as credit card numbers.

2.2. Designated Establishments – Regional Offices of ISED

Please note that as of August 16, 2021, Innovation, Science and Economic Development Canada (ISED) regional mailrooms are no longer considered designated establishments to which correspondence addressed to CIPO may be delivered. These include the mailrooms in Ottawa, Montreal, Toronto, Edmonton, and Vancouver.

Going forward, all correspondence should be submitted electronically, where possible, or delivered in person or sent via registered mail to CIPO at the address indicated in section 2.1 of this page.

2.3. Designated Establishment – Registered Mail™ and Xpresspost™ services of Canada Post

Written communications addressed to the Commissioner of Patents may also be sent via the Registered Mail™ and Xpresspost™ services of Canada Post which are designated establishments for the purposes of the Patent Rules. (section 10 of the Patent Rules)

3.0 Electronic means for submission of written communications

Written communications addressed to the Commissioner of Patents may be submitted using the electronic means only as provided for in this document. Written communications sent online or by facsimile constitutes the original; therefore a duplicate paper copy should not be forwarded.

3.1 Online

Written communications addressed to the Commissioner of Patents may be sent electronically using the relevant links below:

3.1.1. Canada as Receiving Office under the PCT: PCT-SAFE

Pursuant to PCT Rule 89bis, CIPO, in its role as a Receiving Office, accepts the electronic filing of an international application prepared using the latest version of the WIPO's PCT-Safe software and applications prepared using WIPO's ePCT online service. Filing in both cases must be done using CIPO's International Filing e-service called PCT E-Filing.

Note: Communications related to PCT international applications cannot be sent electronically to CIPO using any of the other online submission means outlined above. Alternatively communications related to PCT international applications may be physically delivered by regular mail, in person, to a designated establishment or submitted by facsimile as outlined in this document.

3.2 Facsimile

Facsimile correspondence addressed to the Commissioner of Patents may be sent to the following facsimile numbers:

  • (819) 953-CIPO (2476) or
  • (819) 953-OPIC (6742)

Facsimile correspondence that is sent to any facsimile number other than those indicated above, including those of a designated establishment, will be deemed not to have been received.

The electronic transmittal report returned to you following your facsimile transmission will constitute your acknowledgment receipt. Confidentiality of the facsimile transmission process cannot be guaranteed. Please note that CIPO strongly discourages the use of a computer facsimile interface or internet-based facsimile services due to technical issues with reception.

When submitting a document by facsimile that also has a fee requirement, notification of the preferred mode of payment to be applied must be prominently displayed on the Fee form to ensure expedient processing.

4.0 Electronic forms of submission

The following section outlines other electronic forms for submission of documents, information and fees that may be used in accordance with section 8.1 of the Patent Act, and for the purposes of subsections 10(1), 10(4), 58(1), and 58(4) of the Patent Rules. The Office will accept documents initially filed in other formats provided they are viewable with the software "Stellent Quick View Plus 8.0.0". In these cases, the Office will request the documents to be replaced by documents in PDF or TIFF and the submission of a statement to the effect that the replacement documents are the same as the documents initially filed.

4.1 General requirements for submission of electronic forms

Documents submitted in an electronic form should contain a cover letter and a table of contents which will be date stamped by the Office and placed in the application file.

When submitted in an electronic form, the parts of the application must be broken down in individual files, each being no larger than 25 megabytes.

The Patent Office will accept 3.5 inch diskette, CD-ROM, CD-R, DVD, DVD-R and any format as specified in Annex F of the PCT Administration Instructions.

The electronic medium must also be free of worms, viruses or other malicious content. Files with malicious content will be deleted.

4.2 Types of electronic forms for submission

The Patent Office will accept files in the TIFF, PDF and ASCII format when they comply with the following specifications:

TIFF Format:

  • TIFF CCITT Group 4, single or multi-page, black and white;
  • Resolution of either 300 or 400 dpi;
  • The dimensions of the scanned/stored images should match that of the paper requirements, namely 8 ½" by 11" or A4.

PDF Format:

  • Adobe Portable Document Format Version 1.4 compatible;
  • Non-compressed text to facilitate searching;
  • Unencrypted text;
  • No embedded OLE objects;
  • All fonts must be embedded and licensed for distribution.


  • Shall be encoded using IBM Code Page 437, IBM Code Page 932 or a compatible code page.

4.3 Electronic format requirements for sequence listings

With regards to sequence listings under section 58 of the Patent Rules, if the disclosure of a patent application contains a sequence listing other than identified in the prior art, that sequence listing must be presented in electronic form and in compliance with the PCT sequence listing standard.Footnote 1

4.3.1 Electronic Filing of Sequence Listings in the Receiving Office under PCT

Pursuant to PCT Rules 89bis and 89ter, and in accordance with Part 7 of the PCT Administrative Instructions, where an international application contains disclosure of one or more nucleotide and/or amino acid sequence listings, CIPO, in its role as a receiving Office, accepts that the sequence listing part of the description and/or any table related to the sequence listing(s) be filed, at the option of the applicant:

  • only on an electronic medium in electronic form in accordance with section 702 of Part 7 of the PCT Administrative Instructions; or
  • both on an electronic medium in electronic form and on paper in accordance with section 702 of Part 7 of the PCT Administrative Instructions; provided that the other elements of the international application are filed as otherwise provided for under the PCT.

The sequence listing part of an international application filed in electronic form and related tables filed in electronic form shall comply with the relevant provisions of Annex C of the PCT Administrative Instructions respectively.

For this purpose the Canadian receiving Office will accept any electronic media specified in Annex F of the PCT Administrative Instructions. Where both the sequence listing and the tables are filed in electronic form, the listing and the tables shall be contained on separate electronic media, which shall contain no other programs or files.

For the purpose of processing the international application, the Canadian receiving Office requires two (2) additional copies of the electronic media containing the sequence listing and/or tables in electronic form, accompanied by a statement that the sequence listings and/or tables contained in the copies are identical to those in electronic form as filed.

For further details concerning the filing of sequence listings and/or tables in electronic form, including the labeling of the electronic media and the calculation of the international filing fee, refer to section 7 of the PCT Administrative Instructions.

5.0 Written Communications from the Commissioner of Patents or the Patent Office

The Commissioner of Patents or Patent Office will send written communications to persons doing business before the Patent Office at the address provided in accordance with the Patent Rules. By default, the Office will send written communications to the postal address provided unless the person with whom the Office is corresponding provides both their email address and authorization to send written communications to the latter. (section 7 of the Patent Rules)

5.1 Exceptions – Written Communications sent before Removal or Refusal from Register of Agents

Under uncommon circumstances patent agents may be removed from the register (subsection 23(2) of the Patent Rules) or refused recognition from the Commissioner (section 16 of the Act).

Any written communications sent to the removed or refused agent in the four month period preceding the removal or refusal that has not been responded to, is deemed not sent (section 11 of the Patent Rules).

In practical terms, the applicant will be advised of the removal or refusal of their agent and any written communications sent in the preceding four months will be resent to the applicant. The applicant may also receive a notice requiring an appointment of agent if an agent is required.