Grant is not the end of the argument. For a year after a patent is granted and published, anyone with a real interest in the field can ask the Patent Office to revoke it — without going to court, on the same grounds that were available before grant, and in front of a board that includes technical examiners.
This guide covers who can bring a post-grant opposition, how the exchange of statements and evidence runs, what the Opposition Board does, and what the Controller can order at the end.
Quick reference
| Who can file | A person interested — not anyone |
| When | Within twelve months of the grant being published |
| Form | Form 7, with a written statement and evidence |
| Fee | ₹40,000, with a reduced rate for individuals, startups, small entities and educational institutions |
| Patentee’s reply | Two months — silence means the patent is revoked |
| Opponent’s reply evidence | One month, confined to the patentee’s evidence |
| Opposition Board | Three members; recommendation within two months |
| Outcome | Patent maintained, amended or revoked |
Who is a “person interested”
Unlike pre-grant opposition, which is open to anyone, a post-grant opposition needs standing. The Act defines a person interested as including anyone engaged in, or promoting, research in the same field as the invention. The courts have read it broadly to cover anyone with a direct, present commercial interest — a manufacturer, seller, importer or exporter of the kind of product the patent covers, or a person funding research in the area.
What it excludes is the bystander. A public-interest body without any research or commercial footprint in the field may find its standing challenged, and a challenge to standing is the first thing a well-advised patentee raises.
The window
Twelve months from the date the grant is published in the patent office journal — not from the date of the grant order, and not from the date you noticed it. After twelve months the route closes and the remaining option is a revocation petition, which goes to the High Court.
The grounds
They are the same eleven as for pre-grant opposition. In plain terms: the invention was wrongfully obtained; it was already published or already claimed; it was publicly known or used in India; it is obvious; it is not an invention or is excluded from patenting; the specification does not describe it sufficiently; the applicant failed to disclose its foreign applications or gave false information about them; a convention application was filed late; the source or geographical origin of biological material was not disclosed or was wrongly disclosed; or the invention was anticipated by traditional knowledge.
The opposition must fit within them. A ground not raised in the notice cannot be introduced later without leave.
How it is filed
The opposition is a notice on Form 7, filed with the Controller and accompanied by a written statement setting out the nature of the opponent’s interest, the facts relied on, the grounds, and the relief sought — together with any evidence. A copy goes to the patentee.
Evidence in opposition proceedings is given by affidavit. A written statement that argues a case but attaches nothing sworn is not evidence, and the Delhi High Court has said so in terms — an opposition that turns on prior use or prior knowledge without an affidavit to prove it is an opposition that will fail on that point.
The fee rose sharply in March 2024 as part of the general move to deter tactical oppositions: ₹40,000 for opponents other than individuals, startups, small entities and educational institutions, who pay a reduced rate.
The exchange of evidence
The timetable is fixed and short.
The patentee’s reply — two months. From receipt of the opponent’s statement and evidence, the patentee has two months to file a reply statement and evidence. This is the deadline that decides most oppositions before they are argued, because a patentee who does not reply in time is treated as not contesting, and the patent is deemed revoked. There is no more consequential two months in the life of a patent.
The opponent’s reply evidence — one month. From receipt of the patentee’s reply, the opponent has one month to file evidence in reply, and it must be strictly confined to matters raised in the patentee’s evidence. It is not a second chance to make the original case.
Nothing further without leave. After that, neither side may file more evidence except with the Controller’s permission or direction.
The Opposition Board
Once the evidence is in, the Controller constitutes an Opposition Board of three members — examiners, one of whom chairs — and refers the papers to it. The Board examines the notice, the statements and the evidence on every ground raised, and gives the Controller a reasoned recommendation on each.
Since March 2024 the Board must report within two months of the reference, down from three. The recommendation is not binding, but it is what the Controller starts from, and both parties receive a copy before the hearing.
Hearing and decision
The Controller then hears both sides and decides. Three outcomes are open:
- Maintain the patent as granted.
- Amend it — typically by narrowing the claims to what survives the opposition — and maintain it as amended.
- Revoke it.
The order is reasoned, and it is appealable to the High Court.
Choosing the route
A post-grant opposition is one of three ways to attack a granted patent. The others are a revocation petition to the High Court, available for the life of the patent, and a counter-claim for revocation in an infringement suit the patentee brings against you.
The Supreme Court has held that a challenger cannot run two of these at once on the same grounds — once one route is taken, the others are shut for that party. So the choice matters. Opposition is cheaper, faster and technically expert; revocation before a court carries the weight of a judicial finding and is not limited to the first year. Which is right depends on the patent, the evidence and what you intend to do in the market.
Frequently asked questions
Who can file a post-grant opposition in India? A person interested — someone engaged in or promoting research in the field of the invention, or with a direct commercial interest in the kind of product it covers. Unlike pre-grant opposition, it is not open to anyone.
How long after grant can a patent be opposed? Twelve months from the date the grant is published in the patent office journal. After that, the route is a revocation petition to the High Court.
What happens if the patentee does not reply to a post-grant opposition? The patent is deemed revoked. The patentee has two months from receipt of the opponent’s statement and evidence to file a reply; silence is treated as not contesting.
What is the Opposition Board? A three-member board of examiners constituted by the Controller for each post-grant opposition. It examines the statements and evidence on every ground and gives the Controller a reasoned recommendation, within two months since the 2024 amendment.
Can the Controller amend the patent instead of revoking it? Yes. After hearing both sides the Controller may maintain the patent, amend it — usually by narrowing the claims — or revoke it.
Can I file a post-grant opposition and a revocation petition? Not on the same grounds at the same time. The Supreme Court has held that once a party takes one of the three routes — opposition, revocation petition or counter-claim in an infringement suit — the others are closed to it.
Useful official resources
- IP India — patents — Form 7, fees and the patent office journal
- InPASS — patent search — find the grant publication date
See our related notes on opposing an application before grant and revoking a patent before the High Court.
Served with a post-grant opposition and the two months running, or weighing whether to bring one? Talk to us.