Sequence listings filed with divisional applications: new EPO practice

von Dr. Markus Grammel | 13. November 2023 | Know-How


Since 1 July 2022, any divisional patent application that has been filed on or after that date at the European Patent Office (EPO) and that contains relevant nucleotide or amino acid sequences must include a sequence listing that complies with the new global sequence listing standard, WIPO Standard ST.26. This standard replaces WIPO Standard ST.25 (for further details, please see „New WIPO standard for sequence listings“).

The EPO will soon apply a new practice concerning the handling of these divisional applications (see „Transitional regime for divisional applications with sequence listings“ on the Institute of Professional Representatives before the European Patent Office website).


At the EPO, if the parent application of a divisional application filed on or after 1 July 2022 includes a ST.25-compliant sequence listing, this sequence listing must be converted into one complying with ST.26 in the divisional application. There is a risk of adding or losing subject matter when doing this. To avoid this risk, in addition to the filing of the mandatory ST.26-compliant sequence listing, applicants can file:

  • the parent application’s ST.25 sequence listing in PDF format as part of the divisional application; or
  • the divisional application by reference to the parent application (Rule 40(1)(c) of the European Patent Convention).

Exclusion of ST.25 sequence listings from page fee calculation

Currently, the parent application’s ST.25 sequence listing pages are taken into account when calculating the additional fee for divisional applications exceeding 35 pages. Under the new practice, these pages will be excluded from the page fee calculation, provided the following conditions are met:

The sequence listing is:

  • filed as a separate part of the description in PDF format; or
  • part of the certified copy under Rule 40(3) of the European Patent Convention, if the description of the divisional application is replaced by a reference to the parent application.
  • The sequence listing provided for the parent application complies with ST.25.

Users will be informed of this change of practice in a notice from the EPO to be published in the Official Journal 11/2023. The new practice will apply to all divisional applications for which the page fee will not have been paid.

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