Section 25 of the Patents Act, 1970
Opposition to the patent
Creates India's two-stage opposition system: anyone may object before grant, and any interested person may oppose within a year after grant.
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.
The authority is the enacted text, not this page. Where our wording and the official provision, or an applicable Gazette notification, do not match, the official material prevails.
What this section says, in plain language
Examination is done by one examiner and one Controller working from a search. They cannot know everything. Section 25 lets the public correct that by putting evidence in front of the Controller, at two different moments in the life of an application. This double window is one of the features that makes Indian patent practice distinctive.
The first window is pre-grant opposition. Once an application has been published, any person may make a written representation to the Controller opposing the grant. There is no need to show a business interest; a competitor, an industry body, a patient group or a private citizen can all file. The representation can be made at any time after publication until the patent is granted. Under the current Rules the Controller first considers whether the representation is maintainable, and only then calls on the applicant to respond within the short period the Rules allow. The opponent may also ask to be heard.
The second window is post-grant opposition. Here the door is narrower. Only a person interested, meaning someone engaged in or promoting research or business in the same field, may give notice of opposition, and it must be given within twelve months from the date of publication of the grant. A post-grant opposition is referred to an Opposition Board of examiners, which examines the material and makes a recommendation to the Controller. Evidence is filed on both sides on a timetable set by the Rules, and there is a hearing before the Controller decides.
The grounds are listed in the section and are largely common to both stages. They include that the invention was wrongfully obtained from the opponent, that it was published or claimed earlier, that it was publicly known or publicly used in India before the priority date, that it is obvious, that it is not an invention or is not patentable under the Act, that the specification does not sufficiently and clearly describe the invention, that the applicant failed to disclose information about foreign applications or gave false information, that a convention application was filed out of time, that the source or geographical origin of biological material was not disclosed or was wrongly mentioned, and that the invention was anticipated by knowledge, oral or otherwise, available within any local or indigenous community. The outcome can be refusal or maintenance of the patent, or maintenance in amended form.
Why this section matters
Competitors, generic manufacturers, research institutions, civil society groups and any applicant whose published application attracts attention.
Pre-grant, from publication until the patent is granted; post-grant, within twelve months of the publication of the grant.
A right in the public to challenge a patent before the Controller, and a duty on the Controller to decide the challenge after hearing both sides.
An applicant who does not answer an opposition can lose the patent; a challenger who misses the post-grant window is left with the harder and costlier revocation route.
How it works in practice
A published application and a competitor's file
Marudhar Agritech Pvt Ltd, Jodhpur, published an application claiming a seed coating that improved germination in saline soil. A rival, Deccan Seeds, spotted it and pulled together three items: a state agricultural university bulletin from four years earlier, a dated invoice showing the same coating sold to farmers in Bhuj before the priority date, and an argument that the remaining difference was an obvious change of concentration. Deccan filed a pre-grant representation setting out these grounds with the documents attached. The Controller found the representation maintainable and called on Marudhar to reply. Marudhar amended its claims to a specific two-layer structure that the bulletin nowhere described, and filed comparative germination data. After a hearing the Controller allowed the amended claims and refused the broad ones. Deccan did not stop the patent, but it removed the broad claim that would have blocked its own product. Both sides got something out of the process.
Simplified illustration only. Actual legal outcomes depend on the facts.
Key points to remember
- Pre-grant opposition is open to any person; post-grant opposition only to a person interested.
- Pre-grant runs from publication until grant; post-grant must be filed within twelve months from the publication of the grant.
- The grounds are set out in the section and cover wrongful obtaining, prior publication, prior claiming, public knowledge or use, obviousness, non-patentable subject matter, insufficiency, foreign filing disclosure failures, late convention filing, biological material disclosure and traditional knowledge.
- A post-grant opposition is referred to an Opposition Board, which recommends, while the Controller decides.
- Evidence and hearings follow the timetable in the Rules; both sides can be heard.
- A patent can be refused, maintained, or maintained in amended form.
- Opposition is not the only route; revocation under the Act remains available, including as a counterclaim in an infringement suit.
Common mistakes and misunderstandings
- Thinking pre-grant opposition can be filed before the application is published. The window opens on publication.
- Filing a post-grant opposition without being a person interested. Standing is tested, and a bare curiosity is not enough.
- Assuming a pre-grant representation is a letter that needs no evidence. Bare assertions rarely move a Controller; documents, dates and proof of public availability do.
- Believing that losing an opposition ends the fight. Revocation grounds under the Act survive, and validity can still be attacked in court.
Connected provisions
Indian patent law works in two layers. The Act carries the substance and the Rules carry the machinery. Because the layers are amended by different processes and at different times, they are presented in separate blocks instead of being merged into one description.
Forms, deadlines and fees
The Second Schedule to the Patents Rules contains the prescribed forms. A form that has been amended will not match an older saved copy, so take a fresh download from the official site before you fill anything in.
- A pre-grant representation may be filed at any time after publication of the application and before the patent is granted.
- A notice of post-grant opposition must be given within twelve months from the date of publication of the grant of the patent.
- The periods for the applicant's reply, for evidence and for hearing requests are set by the Rules and should be checked against the current Rules, as they were shortened by recent amendments.
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.
Amendment history
What changed in this provision, newest first. Read the footnotes in the official consolidated text for the full record.
- 2005The Patents (Amendment) Act, 2005Opposition was rebuilt in two stages. Any person may make a representation against an application before grant, and a person interested may oppose the patent after grant before the Controller, with an Opposition Board reporting on the case. The grounds were restated.
- 2002The Patents (Amendment) Act, 2002The grounds were extended to cover failure to disclose, or wrong disclosure of, the source of biological material, and anticipation by knowledge, including oral knowledge, available within any local or indigenous community.
Compiled from official consolidated texts and Gazette notifications. See the site-wide change log.
Related judgments
Dr. Aloys Wobben & Anr. v. Yogesh Mehra & Others
(2014) 15 SCC 360; AIR 2014 SC 2210 (Civil Appeal No. 6718 of 2013) · Judgment source ↗
Question before the courtWhether the same person may challenge a patent by post-grant opposition, by a revocation petition and by a counter-claim all at once.
HeldThe Court held that these routes are alternatives rather than additions. Once a person has pursued a post-grant opposition to its conclusion, the same person cannot then run a revocation petition on the same grounds. A person who files a revocation petition before an infringement suit begins cannot later seek revocation by counter-claim in that suit, and a person who files a counter-claim cannot afterwards start a separate revocation petition. The word or in the revocation provision was read as offering a choice.
Case notes are written in our own words from the judgment and are published only after legal review. They are not advice and not a prediction about any other matter. All case notes.
Questions people ask about Section 25
What is the difference between pre-grant and post-grant opposition?
Pre-grant opposition is a written representation that any person may make after the application is published and before the patent is granted. Post-grant opposition is a formal notice that only a person interested may give, within twelve months from the publication of the grant, and it is referred to an Opposition Board before the Controller decides. Pre-grant is quicker and cheaper; post-grant is a fuller proceeding with structured evidence.
Who is a person interested?
Broadly, someone with a real stake in the field, such as a manufacturer, a researcher, an institution or an association engaged in or promoting research or business in the same area as the invention. The requirement filters out strangers with no connection to the technology. It applies to post-grant opposition and to revocation, but not to pre-grant representations, which anyone may file.
Can the same person file both a pre-grant and a post-grant opposition?
In principle the two are separate remedies with different requirements, and using one does not automatically bar the other. In practice a Controller will look closely at a post-grant opposition that simply repeats a rejected pre-grant case on the same evidence. The stronger approach is to bring genuinely new material, or to reserve the best evidence for the stage where it will be tested properly.
Does filing an opposition stop the patent from being granted?
A pre-grant representation that is found maintainable must be considered before the Controller decides on grant, so it does hold up the decision. It does not automatically defeat the application. Many oppositions end with the patent being granted on narrower claims. A post-grant opposition does not undo the grant while it is pending; the patent stays in force unless and until the Controller orders otherwise.
What happens if I miss the twelve-month post-grant window?
The post-grant route closes, but the patent can still be challenged. Revocation under the Act can be sought by a person interested, and validity can be attacked by way of counterclaim if the patentee sues for infringement. Those routes are generally slower and more expensive than opposition before the Controller, which is why the twelve-month window is worth watching in fields you care about.
Need to oppose a patent, or defend one?
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