What are the requirements for submitting a “Sequence Listing” in an international application (PCT) via the USPTO patent electronic filing system?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

When submitting a “Sequence Listing” in an international application (PCT) via the USPTO patent electronic filing system, there are specific requirements and recommendations:

• It is highly recommended to submit the sequence listing as a single ASCII plain text file with a “.txt” extension on the international filing date.
• The size limit for submitting a sequence listing ASCII plain text file is 100 megabytes.
• The check list (Box No. IX) of the PCT Request (form PCT/RO/101) must indicate that the sequence listing submitted as an ASCII plain text file forms part of the international application.
• If submitted as an ASCII plain text file, no additional copies (including PDF image files) should be submitted.

The MPEP states: “When filing an international application (PCT) using the USPTO patent electronic filing system, it is highly recommended to submit a sequence listing as a single ASCII plain text file with a ‘.txt’ extension on the international filing date.”

If the sequence listing is submitted as an ASCII plain text file, it will serve both as the sequence listing part of the description required under PCT Rule 5.2 and the electronic form under PCT Rule 13ter.1(a).