Opposition before the granting office: documents to prepare
Opposition before the granting office turns on paperwork, not persuasion. A party who wants to file needs a complete case ready before the opposition window opens: grounds, prior art, and evidence arranged in one file. Nothing filed after the deadline extends the record, because the office is not required to wait for it.
What changes once the opposition window opens
The moment the granting office publishes the grant, a fixed window starts to run. Inside that window, any third party with standing can challenge the patent without first going to court. Once the window closes, the same challenge usually has to move to a separate revocation track, with its own cost and its own timing. The practical effect is simple: whatever is missing on day one of the window stays missing for the rest of it, because late submissions are treated as new material, not as a continuation of the file already open.
Who may file, and why standing matters
Under the rules applied by the relevant granting office, opposition is normally open to any interested party, not only to a direct competitor. A party does not usually have to prove a commercial stake to be heard, but it does have to identify itself correctly and act within the deadline the office sets. Filing through a representative without the right paperwork behind that representative is a common way to lose weeks before the substance of the case is even reached.
Documents to prepare before filing
The office will not accept an opposition built on a single page of argument. A complete file, ready before the window opens, normally covers the items below.
| Document | Purpose | When it is needed |
|---|---|---|
| Notice of opposition | States who is opposing and against which patent | At filing |
| Statement of grounds | Sets out, point by point, why the patent should not stand | At filing, or shortly after |
| Prior art and other evidence | Supports each ground with a document, not a claim | At filing |
| Proof of standing and identity | Confirms who is entitled to oppose and who represents them | At filing |
| Translations, where required | Puts foreign-language evidence into a form the office can review | Before the file is examined |
| Fee payment record | Confirms the filing fee was paid and matches the file | At filing |
Where the cited prior art sits online rather than in a printed journal, capture it in full at the point of filing. Web pages get edited or taken down entirely, and a citation that cannot later be reproduced carries little weight. When the referenced work is removed explained sets out who decides what happens to a reference once its source disappears, which is worth reading before the evidence bundle is closed.
Each row above answers a question the office will ask in its own order, not in the order convenient to the party opposing the patent. Missing one line item does not pause the clock. It simply narrows what can still be argued once the window has closed.
Assembling the file: order of work
- Ask the inventor or the technical team to confirm, in writing, every publication that predates the filing date.
- Instruct counsel to draft the statement of grounds before the deadline, not on the day it falls due.
- Have a translator prepare any foreign-language evidence in parallel, so it is not the last piece missing.
- Confirm with the finance function that the filing fee is paid and the receipt is filed with the record.
- Ask the representative to check the notice of opposition against the office's own naming and formatting rules before it is sent.
None of these steps is optional on its own, but the order can be adjusted. What cannot be adjusted is the deadline itself.
Who decides, and on what timeline
The granting office itself decides the opposition, usually through a panel rather than a single examiner. The panel reviews the grounds filed, invites a response from the patent holder, and can call oral proceedings before deciding whether the patent stands, falls, or survives in narrowed form. The decision is issued in writing and is open to appeal within the office's own appellate structure, before any court becomes involved at all.
Costs built into the procedure
The filing fee is set by the granting office and published in its own tariff, alongside any separate fee for appeal. Beyond the office's own fee, cost is driven mainly by the number of grounds raised and by whether oral proceedings are called, not by the length of the notice itself.
Two situations that change the file
If the patent holder does not respond inside the time given, the office proceeds on the file as it stands. Silence does not amount to consent, but it does remove the chance to rebut individual grounds one by one. If a settlement is reached before a decision, both sides normally still have to notify the office directly; the panel can decide regardless of any private agreement between them. If new prior art surfaces after filing, it can usually still be added, but only inside the timetable the panel sets, not on the opposing party's own schedule.
What this page does not cover
This page covers the domestic opposition procedure at the granting office. It does not cover litigation on validity once a patent has already survived opposition, and it does not cover a claim for damages arising from any infringement uncovered along the way. It also does not extend to the underlying commercial relationship that made the patent worth challenging in the first place. Where a counterparty sits behind that relationship, that assessment belongs with Counterparty report before renewing a contract in detail, not with the opposition file itself.
Verified
This material reflects the procedural sequence used before granting offices generally and was last checked in the first quarter of 2025. It draws on publicly available guidance issued by the relevant office rather than on any single statutory provision, in keeping with how the page is meant to be used: as a checklist, not as a citation. The firm's scope and the material it publishes are set out in About the firm and its scope explained.
Related reading
For the stage that follows once the opposition window has already closed, see Revocation proceedings step by step.
If the dispute already spans more than one jurisdiction and more than one owner of the underlying rights, start with When the team is spread across three countries step.
FAQ
How long does opposition before the granting office take in practice?
Timing depends on the office's own calendar and on how many grounds are raised. Expect a written exchange between the parties first, then a decision that can take substantially longer once oral proceedings are called.
Which documents are needed to start?
At minimum: a notice naming the opposing party and the patent, a statement of grounds, the prior art or other evidence behind each ground, proof of standing, and the fee payment record. The table above sets out what each one is for.
What happens if the other side does not respond?
The office proceeds on the file it has. A patent holder who stays silent loses the chance to rebut the grounds raised, but silence alone does not decide the case; the panel still weighs the evidence filed.