Rules 21 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Rules 21 to 23 close Chapter III. Rule 21 deals with the priority document and any translation of it for an international application designating India. Rule 22 states the consequence of failing to meet the requirements of rule 20. Rule 23 says that the Chapter supplements the Patent Cooperation Treaty and that, in a conflict, the Treaty and its regulations and administrative instructions apply.
If the applicant has not complied with Rule 17.1(a), (b) or (b-bis) of the PCT regulations, the priority document must be filed in the Patent Office before the thirty-one month limit in rule 20(4) (rule 21(1)). An English translation of a non-English priority document, where Rule 51bis.1(e)(i) or (ii) applies, must be filed in the same time (rule 21(2)). On default, the Patent Office invites the applicant to file within three months from the invitation; failing that, the priority claim is disregarded for the purposes of the Act (rule 21(3)). Non-compliance with rule 20 leads to deemed withdrawal (rule 22). On any conflict, the Treaty prevails (rule 23).
Rule 21: filing of the priority document
The printed rule opens "(1) Filing of priority document - (1)", with the heading text and the sub-rule number repeated. It is read as sub-rule (1).
Sub-rule (1): the priority document
Where the applicant in respect of an international application designating India has not complied with the requirements of paragraphs (a), (b) or (b-bis) of rule 17.1 of the regulations under the Patent Cooperation Treaty, and subject to paragraph (d) of that rule, the applicant shall file the priority document referred to in that rule before the expiration of the time limit referred to in sub-rule (4) of rule 20 in the Patent Office.
Rule 21(1) applies only where the requirements of Rule 17.1 of the Treaty regulations have not been complied with. The time limit is the thirty-one months from the priority date set in rule 20(4)(i); see our article on rule 20.
Sub-rule (2): translation
Where sub-paragraph (i) or (ii) of paragraph (e) of rule 51bis.1 of the regulations under the PCT is applicable, an English translation of the priority document, duly verified by the applicant or the person duly authorised by him, shall be filed within the time limit specified in sub-rule (4) of rule 20.
The Rules do not set out the content of Rule 51bis.1(e); the reader must consult the PCT regulations to know when it applies. The verification requirement is the same as in rule 20(3)(b): the translation must be verified as correct by the applicant or an authorised person.
If you want help working out whether your priority document is already on the international file or must be filed in India, our patent drafting and filing service can check the position before the limit runs.
Sub-rule (3): invitation, three months, and loss of priority
Where the applicant does not comply with sub-rule (1) or (2), the Patent Office shall invite the applicant to file the priority document or the translation, as the case may be, within three months from the date of such invitation. If the applicant fails to do so, the claim of the applicant for the priority shall be disregarded for the purposes of the Act.
| Stage | What happens | Period |
|---|---|---|
| Default under rule 21(1) or (2) | Patent Office invites the applicant to file the priority document or translation | Applicant has three months from the date of the invitation |
| No response within three months | The priority claim is disregarded for the purposes of the Act | Consequence stated in rule 21(3) |
| Rule 137(2) (inserted in 2024) | Lists rule 21 among the matters to which the general power in rule 137(1) does not apply | Rule 137(1) is the general power to correct irregularities |
The rule does not spell out further consequences of the priority claim being disregarded. For the meaning of priority date, see our article on section 2 (Convention, PCT, priority date and interpretation) and the guide on convention applications and Paris Convention priority.
Rule 22: effect of non-compliance
"An international application designating India shall be deemed to be withdrawn if the applicant does not comply with the requirements of rule 20." The consequence is stated without discretion in the text: the application is deemed withdrawn. The requirements of rule 20 include the Form, the fee, the translation and the time limit of thirty-one months. Rule 22 does not itself refer to rule 21, so the loss of a priority claim under rule 21(3) is a separate consequence from deemed withdrawal under rule 22.
Rule 23: the Treaty prevails
- Sub-rule (1). The provisions of Chapter III shall be supplemental to the PCT and the regulations and the administrative instructions made thereunder.
- Sub-rule (2). In case of a conflict between any provision of the rules in the Chapter and the provisions of the Treaty and the regulations and administrative instructions, the Treaty provisions shall apply in relation to international applications.
This means that the Indian Rules do not replace the Treaty; they fill gaps and add national requirements. Where the two clash, the Treaty, its regulations and administrative instructions govern. For the Act side, see our articles on section 135 (convention applications) and sections 138-139 (supplementary provisions for convention applications).
A worked example
Pinnacle Dye Works enters the Indian national phase for an international application that claims priority from an earlier foreign filing. It has not satisfied the Treaty regulation requirements about the priority document in the international phase. Under rule 21(1) it must file the priority document in the Patent Office before the thirty-one month limit in rule 20(4). The priority document is in a language other than English and Rule 51bis.1(e)(i) applies, so under rule 21(2) it also files a verified English translation within the same time.
Pinnacle overlooks both. The Patent Office issues an invitation under rule 21(3). Pinnacle then has three months from the date of the invitation. If it still does nothing, the claim for priority is disregarded for the purposes of the Act. Had Pinnacle failed altogether to meet rule 20 (for example, by not paying the national fee in time), rule 22 would deem the application withdrawn.
Checklist
- Confirm whether the priority document was already handled in the international phase.
- If not, file it in the Patent Office before the limit in rule 20(4).
- File a verified English translation where Rule 51bis.1(e)(i) or (ii) applies.
- Respond within three months of any invitation.
- Remember that the Treaty prevails over the Chapter in a conflict.
Need help with priority documents?
Losing a priority claim is a serious step, and the periods are short. If you want your national phase papers reviewed for the priority document and translation, you can contact us about patent drafting and filing.
Key takeaways
- Rule 21 requires the priority document, and a verified English translation where Rule 51bis.1(e)(i) or (ii) applies, within the rule 20(4) limit.
- On default, the office invites compliance and gives three months from the invitation.
- Failing that, the priority claim is disregarded for the purposes of the Act.
- Rule 22 deems an international application designating India withdrawn if rule 20 is not complied with.
- Rule 23 makes the Chapter supplemental to the Treaty, which prevails in a conflict.
- Check amendments after the Second Amendment Rules, 2024.
Read next
- Rule 20: national phase applications designating or electing India
- Rules 17 to 19: PCT definitions, appropriate office and international applications
- Convention application for patent: Paris Convention priority
- Patent Cooperation Treaty: national phase entry in India
Disclaimer: Based on the Patents Rules, 2003 as consolidated up to 21 September 2021 and as amended by the Patents (Amendment) Rules, 2024 and the Patents (Second Amendment) Rules, 2024, as consulted on 2 October 2026. Later amendment rules, forms and fees should be checked in their current form. This article is general information, not legal advice; check the official text before acting.