Section 138 of the Patents Act, 1970
Supplementary provisions as to convention applications
Deals with proof of foreign filings for convention applications and treats an international application designating India as a complete specification.
Official legal text
The verbatim statutory text of this provision is reproduced from the official source and checked by our legal reviewer before it is published here. Until that check is complete for this page, read the exact wording directly from the official source linked below — it is the only version that governs.
Read this as a plain-language summary. If it and the official text, or a relevant Gazette notification, say different things, the official text and the notification are what count.
What this section says, in plain language
A priority claim is only as good as the proof behind it. Section 138 is where that proof is regulated. When a convention application is filed, the applicant may be required to furnish a copy of the specification, drawings and other documents filed in the convention country, certified by the official head of the patent office of that country or otherwise verified to the Controller's satisfaction. Where those documents are in a language other than English, a verified English translation has to be supplied.
The section also settles a question that would otherwise be open to argument. The date on which an application was made in a convention country is the date the Controller is satisfied it was made, on the basis of a certificate from the official head of that country's patent office or other acceptable proof. This keeps the Indian proceeding from turning into an enquiry into foreign filing practice, and it gives the applicant a clear way to establish the date.
Section 138 also carries the provisions that make the national phase work. Where an international application designating India has been filed under the Patent Cooperation Treaty, the title, description, claims, abstract and drawings filed in that international application are taken as the complete specification for the purposes of the Act, and the filing date of the application and its complete specification is the international filing date accorded under the Treaty. This is why entering the Indian national phase is a continuation of one application rather than the start of a fresh one.
The practical machinery sits in the rules. Rule 20 deals with international applications designating India, rule 21 with filing of priority documents, and rule 22 with the effect of not complying with certain requirements. Applicants entering the national phase should also remember that amendments are usually made at entry, that the Indian address for service must be in place, and that the statement and undertaking regarding foreign applications under section 8 still has to be filed.
Read together, this section explains why the paperwork around priority is treated so seriously in Indian practice. The earlier date is a substantive advantage, and the Act asks the applicant to prove entitlement to it in a way that an examiner, an opponent or a court can verify.
Why this section matters
Applicants entering India from a Patent Cooperation Treaty application, convention applicants, and their Indian agents.
At national phase entry, when priority documents are called for, and whenever a priority date is challenged.
A duty to prove the foreign filing and its date, and a rule that treats the international application as the complete specification with the international filing date.
The priority claim can fail for want of proof, or an applicant can misunderstand what document and date the Indian case actually runs on.
How it works in practice
A national phase entry that nearly lost its date
Sarayu Medtech Pvt Ltd of Hyderabad files an international application under the Patent Cooperation Treaty designating India, claiming priority from its earlier Indian filing for a portable infusion monitor. When the Indian national phase is entered, a junior executive in the company assumes a new application has been created and starts counting deadlines from the national phase entry date. The company's agent corrects this. Under section 138, the description, claims, abstract and drawings of the international application are taken as the complete specification, and the filing date is the international filing date. That single point resets the internal calendar: publication, the request for examination and the term all have to be worked out on the correct basis. The team also files the priority document request and the section 8 statement, and updates the address for service. Nothing was lost, but the incident becomes the reason the company now keeps a one page date sheet for every international family it brings into India.
Simplified illustration only. Actual legal outcomes depend on the facts.
Key points to remember
- The Controller may require certified copies of the documents filed in the convention country, with a verified English translation where needed.
- The date of the foreign application is established by a certificate from the foreign patent office or other proof acceptable to the Controller.
- For an international application designating India, the description, claims, abstract and drawings are taken as the complete specification.
- The filing date in such a case is the international filing date accorded under the Patent Cooperation Treaty.
- Rules 20, 21 and 22 supply the procedure and the consequences of non-compliance.
- The obligations under section 8 continue to apply to applications that come into India this way.
Common mistakes and misunderstandings
- Treating national phase entry as the filing of a new application. The filing date is the international filing date.
- Leaving translation of the priority document until an objection is raised, when the time allowed may already be short.
- Assuming the Patent Office will accept an uncertified copy of the foreign application as proof of the filing date.
- Forgetting that entering the national phase does not remove the section 8 duty to disclose corresponding foreign applications.
Connected provisions
The Patents Act sets the requirement; the Patents Rules, 2003 set the procedure that carries it out. Parliament passes the Act and the Central Government makes the Rules, so the two are separate instruments. We list the connected rules here to take you from the principle to the paperwork.
Forms, deadlines and fees
Any form mentioned here is prescribed by the Second Schedule. Amendments to the Rules often bring new versions of forms with them, so use the version currently published by the Patent Office, not a template from a book or an old file.
- Priority documents and verified English translations must be furnished within the period allowed by rule 21; confirm the current period before relying on it.
- Publication of the application follows the eighteen month rule in section 11A counted from the date of filing or the priority date, whichever is earlier.
- The request for examination has to be made within thirty one months from the priority date or the filing date, whichever is earlier, under rule 24B as amended in 2024.
Open the deadline calculator — and have every date confirmed against the current Rules before you rely on it.
Fees are prescribed in the First Schedule to the Patents Rules. Because the Schedule is revised from time to time, and charges different amounts to different categories of applicant and for physical as against electronic filing, this page describes the fee without stating a figure. How Indian patent fees work.
Related judgments
Case law is added slowly and deliberately. A summary is drafted, checked against the reported judgment and then reviewed before publication, because a wrong case note can mislead a reader badly. No summary for this provision has reached publication yet. How case notes are prepared.
Questions people ask about Section 138
What is the filing date of an Indian national phase application?
It is the international filing date accorded under the Patent Cooperation Treaty, not the date on which you entered the Indian national phase. Section 138 also provides that the description, claims, abstract and drawings of the international application are taken as the complete specification for the purposes of the Act. This matters for calculating publication, the request for examination and the term of the patent, so getting it right at entry avoids a chain of miscalculated dates.
Do I have to file a priority document in India?
Where priority is claimed, the Controller may require a certified copy of the basic application and, if it is not in English, a verified English translation. Rule 21 sets out the procedure, and in some situations the document can be retrieved through a digital library arrangement instead of being filed on paper. Rule 22 deals with what happens if the requirement is not met, and the practical consequence of default is that the priority date can be lost.
Who certifies the foreign application for use in India?
The official head of the patent office in the convention country certifies the copy, or the documents are otherwise verified to the satisfaction of the Controller. The same source establishes the date on which the foreign application was made. This is why applicants order certified copies early rather than waiting for an objection: obtaining a certified copy and a verified translation from a foreign office can take weeks, and the Indian timetable does not pause while you wait.
Does section 8 still apply to a national phase application?
Yes. The obligation to give information and an undertaking about corresponding applications filed outside India is independent of the route by which the Indian application arrived. It has to be complied with in the prescribed form and kept updated as foreign prosecution moves. Non-compliance with section 8 is a recognised ground of attack in opposition and revocation, and it is one of the more avoidable ways to weaken an otherwise strong patent.
Entering India from a PCT or convention filing?
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