Pre-Grant vs Post-Grant Opposition in India: Which Route Applies
Section 25 of the Patents Act, 1970 gives the public two chances to challenge a patent at the Patent Office. The first comes before the patent is granted. The second comes after. They share a name, a section number and most of their grounds, so they are often treated as one procedure with a different starting date. In practice they behave very differently.
The differences that matter are who can file, when the window opens and closes, how much process the opponent gets, and what the Controller can do at the end. A pre-grant representation can be filed by anyone and is closer to a submission that assists the examiner. A post-grant opposition is a full inter partes proceeding, restricted to a person interested, with an Opposition Board, pleadings, evidence and a hearing.
Choosing the wrong route wastes the only clean opportunity a challenger may get. File post-grant too late and the window has closed. Rely only on a pre-grant representation and you may find the Controller has dealt with it briefly and moved on. This page compares the two routes on the points that decide which one is available to you.
Side by side
| Question | Pre-grant opposition | Post-grant opposition |
|---|---|---|
| Statutory basis | Section 25(1), with procedure in Rule 55. | Section 25(2), with procedure in Rules 55A, 56, 57 and the rules that follow on evidence and hearing. |
| Who may file | Any person. No interest in the invention needs to be shown. | Only a person interested, a term defined in the Act and read as requiring a real stake in the field. |
| Window | After the application is published and before the patent is granted. | Within twelve months from the date on which the grant is published. |
| Nature of the proceeding | A written representation to the Controller, which the Controller considers alongside examination. | A contested proceeding between two parties, with pleadings and evidence on both sides. |
| Link to examination | The Controller takes the representation up once a request for examination is on record, so it runs beside the examination itself. | Examination is over. The proceeding attacks a patent that already exists on the register. |
| Threshold check | Under the Rules as amended in 2024, the Controller first decides whether the representation is maintainable before going further. | The notice must be filed by a person interested within the window; maintainability turns mainly on standing and timing. |
| Opposition Board | No Board. The Controller decides. | The Controller constitutes an Opposition Board of examiners, which examines the material and makes a recommendation. |
| Evidence | The opponent files a statement and any evidence with the representation. Later evidence is limited. | There is a structured sequence: written statement and evidence, reply statement and evidence, reply evidence, and further evidence only with leave. |
| Hearing | A hearing may be requested and is granted where the Controller thinks it necessary. | A hearing is part of the normal course of the proceeding. |
| Effect on the applicant | The application may be refused or the applicant may be required to amend before grant. | The patent already in force may be revoked, maintained, or maintained in amended form. |
| Cost and effort for the challenger | Lighter. A focused document with the best prior art can be enough to change the shape of the claims. | Heavier. It is run like litigation before the Controller, over a longer period. |
| Effect on timing of grant | Can delay grant while the representation is dealt with. | No effect on grant; the patent is already granted and enforceable unless and until revoked. |
The pre-grant route in outline
Once an application is published under section 11A, its specification is open to the public. From that moment until the patent is granted, anyone may write to the Controller saying the application should not proceed, and set out why. The grounds available are the familiar list: the invention was already known or used, it was obvious, it falls in section 3, the specification does not describe the invention properly, information about foreign applications was not given, and so on.
The Controller does not act on the representation in isolation. It is taken up in step with examination, and it is only considered after a request for examination is on record. Under the Rules as amended in 2024 the Controller first forms a view on whether the representation is maintainable at all, which was introduced to filter out filings made only to slow an application down.
The strength of this route is its low cost and its timing. If the best prior art reaches the examiner before the claims are settled, the claims that emerge are usually narrower. The weakness is that the opponent has limited control over the process and no automatic right to a full contest.
The post-grant route in outline
After grant is published, a person interested has twelve months to file a notice of opposition. Person interested is a defined expression, and it is read as covering someone engaged in, or promoting research in, the same field. A competitor, a research institution or an industry body will usually qualify. A stranger with no connection will not.
What follows is a proper contest. The opponent files a written statement and evidence. The patentee replies with a statement and evidence. The opponent may file reply evidence. Further evidence needs the Controller's leave. Separately, the Controller constitutes an Opposition Board made up of examiners, which studies the material and gives a recommendation before the hearing.
At the end the Controller can revoke the patent, maintain it as it stands, or allow amendments and maintain it in the amended form. Until that happens the patent remains on the register and the patentee can act on it.
Choosing between them, and using both
Nothing in the Act forces a challenger to pick one route for all time. A party may file a pre-grant representation, see the patent granted anyway, and then file a post-grant opposition within the window, provided it qualifies as a person interested.
But there is a practical cost to repetition. If the same prior art has already been considered and dealt with by the Controller before grant, running it again afterwards without anything new rarely improves the result. Challengers who use both routes usually keep their strongest material, particularly evidence of prior public use or prior sale that needs witnesses, for the post-grant stage where evidence can properly be filed and tested.
There is also a third route that is not opposition at all. Revocation under section 64 is available to a person interested at any time during the life of the patent, and can also be raised as a counterclaim in an infringement suit. Where the twelve-month window has closed, that is the remaining path.
What the patentee should expect
From the applicant's side, a pre-grant representation is an interruption rather than a crisis. The reply is a technical answer to the cited material, filed within the period the Controller sets. Where the representation lands on something real, narrowing the claims early is often a better outcome than a granted claim that will not survive a later attack.
A post-grant opposition is a bigger commitment. Evidence has to be gathered, expert material may be needed, and the Opposition Board recommendation carries weight at the hearing. The patentee should also consider whether an amendment under the amendment provisions could remove the vulnerability while keeping commercially useful scope.
Which one applies to you
Pre-grant opposition
- The application is published but not yet granted, and you want the examiner to see prior art the search missed.
- You have no direct commercial interest and would not qualify as a person interested.
- Your material is documentary prior art that speaks for itself and needs no witness evidence.
- You want a low-cost intervention that may narrow the claims before they are fixed.
Post-grant opposition
- The patent has been granted and the twelve-month window from publication of grant is still open.
- You are a competitor, supplier, researcher or industry body with a real stake in the field.
- Your case rests on evidence that needs to be filed and tested, such as prior use, prior sale or expert opinion.
- You want a decision that can remove the patent from the register rather than merely influence its scope.
Where people go wrong
- Assuming the twelve-month post-grant window runs from the date of the grant order. It runs from the date the grant is published.
- Filing a post-grant opposition without establishing standing. Any person can file pre-grant, but the post-grant route is limited to a person interested.
- Treating a pre-grant representation as a full trial. Evidence rights are limited, and material held back for a hearing that never happens is material wasted.
- Believing a failed pre-grant representation ends the matter. Post-grant opposition and revocation under section 64 remain available to a qualifying party.
- Missing that a patent stays enforceable while a post-grant opposition is pending. Filing the opposition does not suspend the patentee's rights.
Two attempts on the same application
What follows is a simplified illustration only, and no real matter is described. Verdanta Agro Pvt Ltd of Nashik notices a published application from a rival covering a seed coating process. A retired chemist, with no stake in the business, files a pre-grant representation attaching a decade-old technical bulletin from a farmers cooperative. The Controller finds the representation maintainable, puts the bulletin to the applicant, and the applicant narrows its claims to a specific polymer blend to get around it. The patent is granted on the narrower claims. Verdanta, which sells a competing coating, now qualifies as a person interested. Within twelve months of the grant being published, it files a post-grant opposition. This time the case rests on invoices and delivery records showing that the same polymer blend was supplied to a Kolhapur mill years earlier. That is prior use, and it needs witnesses and documents. The post-grant route gives Verdanta the evidence procedure that the pre-grant route never could.
Simplified illustration only. Actual outcomes depend on the facts.
Questions people ask
Can the same party file both a pre-grant and a post-grant opposition?
Yes, provided it qualifies as a person interested for the post-grant stage. The Act does not bar a party that filed a representation before grant from filing a notice of opposition afterwards. What it will not do is make weak material stronger. If the Controller has already examined the same documents and rejected the argument, repeating it without new evidence rarely changes the outcome. Most challengers therefore keep evidence that needs witnesses, such as prior use, for the post-grant proceeding where it can properly be filed.
What happens if the twelve-month post-grant window has closed?
The opposition route is gone, but the patent can still be attacked. A person interested may file a revocation petition under section 64 at any point while the patent is in force. Validity can also be put in issue by way of counterclaim if the patentee sues for infringement. Those routes go to the High Court rather than to the Controller, so they are longer and more expensive, but the grounds available are broadly the same as those in opposition.
Does filing an opposition stop the patentee from suing?
No. A granted patent remains on the register and remains enforceable while a post-grant opposition is pending. The patentee can send notices and can start proceedings. Courts do take a pending opposition into account when deciding whether to grant an interim injunction, because it goes to how settled the patent looks, but the opposition itself creates no automatic stay. A challenger who needs breathing room has to ask the court for it, not the Controller.
Who counts as a person interested?
The Act defines the expression, and it is read as covering someone with a genuine stake in the subject matter: a person engaged in, or in promoting research in, the same field as the invention. Competitors, manufacturers, suppliers, research institutions and industry associations usually qualify. A person with no connection to the technology generally does not. Standing is checked, so a post-grant opponent should be ready to show what it does and how the patent affects it. No such requirement applies before grant.
What is the Opposition Board and does it decide the case?
In a post-grant opposition the Controller constitutes a Board of examiners to look at the notice, the statements and the evidence, and to make a recommendation. The Board does not decide the opposition. It produces a reasoned view that goes to the Controller, who hears the parties and then decides whether to revoke the patent, maintain it, or maintain it in amended form. There is no equivalent body in the pre-grant route, where the Controller works with the examination file directly.
Deciding which opposition route is still open?
MYCrave Consultancy assesses standing, timing and the strength of your material before you commit to a route.