EPO guide
The European search report and EESR: how to read and respond
By Raj Sutariya, Co-founder, PatentAssist.ai
Updated
The extended European search report (EESR) is the first real verdict the EPO gives on your application. It pairs a list of prior-art documents, each tagged X, Y, A or another category, with a written opinion on patentability. You usually receive it about six months after filing, and you must answer any objections in it before examination starts. This guide explains what each part means, when the search can be limited, and the deadlines that follow.
Based on the EPC, the EPO Guidelines for Examination (April 2026) and the Rules relating to Fees in force from 1 April 2026, checked on 26 October 2026.
Quick answer
- EESR = European search report (Rule 61 EPC) + search opinion (Rule 62).
- X = kills novelty or inventive step alone; Y = kills inventive step in combination; A = background only.
- Deadline: reply to a negative search opinion within 6 months of the Bulletin mentioning the search report, the same date by which you pay the examination fee (€2,010) and the designation fee (€720). Silence means the application is deemed withdrawn (Rule 70a(3)).
- Limited searches: Rule 62a and Rule 63 invitations give you 2 months, with no further processing if you miss them.
What the extended European search report contains
The EESR has two parts (Guidelines B-XI, 1). The first is the search report itself. Under Rule 61 EPC, it lists the documents that may be taken into account in deciding whether the invention is new and inventive, links each citation to the claims it relates to, identifies the relevant passages where appropriate, distinguishes documents by date relative to your priority and filing dates, and gives the IPC classification. In practice the report has:
- A main page with the application number, classification, the technical fields searched (as IPC symbols), the citations and the name of the examiner who searched.
- Supplemental sheet A, which approves or amends the title, abstract and the figure to publish with it.
- Supplemental sheet B, only when the search was restricted: unpaid claims fees, lack of unity, or a limitation under Rule 62a or Rule 63.
- An "Information on Search Strategy" sheet listing the databases, classification symbols and keywords used, and an annex listing family members of the cited patent documents.
The second part is the search opinion (Rule 62): the search division's view on whether the application and invention seem to meet the EPC. It is not published with the search report (Rule 62(2)). The EPO sends you the cited documents with the report (Rule 65).
The publication code tells you which kind of report you are looking at (Guidelines B-X, 4): A1 when the application and search report are published together, A2 when the application is published before the search is done, A3 for the search report published later on its own, and A4 for a supplementary European search report on a PCT application.
Citation categories: X, Y, A, P, E, D, T, O and L
Every cited document gets one or more letters in the first column of the report. Letters can be combined, so "P,X" is an intermediate document that is particularly relevant on its own. The definitions come from Guidelines B-X, 9.2.
| Code | Meaning | What it means for you |
|---|---|---|
| X | Particularly relevant on its own: the document alone shows the claim is not new or not inventive. | The main threat. Find the feature the document lacks, or amend to add one. |
| Y | Particularly relevant in combination: the claim lacks inventive step when this document is combined with one or more other Y documents. | Attack the combination: why would the skilled person not combine them, or what would they still not reach? |
| A | Background art that does not prejudice novelty or inventive step. | No objection by itself. Often a candidate for the background section. |
| O | Refers to a non-written disclosure, such as a talk at a conference. Always paired with X, Y or A. | Check the date of the oral disclosure, not just the date of the document. |
| P | Intermediate document, published between the priority date and the filing date (or on the priority date). Always paired with X, Y or A. | Only prior art if your priority claim fails. Check the priority document supports the claims. |
| T | Theory or principle behind the invention, or evidence that its reasoning or facts are wrong. May be published at any time. | Not prior art; read it as evidence, often for a sufficiency or support objection. |
| E | Earlier patent document: filed or with priority before your filing date but published on or after it. | Counts for novelty only (Art. 54(3) EPC), never for inventive step. |
| D | Document already cited in your own application. Combined with a relevance letter, as in D,X. | Expect the examiner to start from it as the closest prior art. |
| L | Cited for another reason: it casts doubt on a priority claim, proves another citation's date, or relates to double patenting. | Read the stated reason; it may not be tied to any claim. |
| & | Member of the same patent family as the document above it, such as an English family member of a Japanese publication. | Use it to read a non-English citation; the prior-art date is the original's. |
Reading a citation line
One document can carry different categories for different claims. The Guidelines (B-X, 9.3) give this example:
| Category | Citation and passages | Claims |
|---|---|---|
| X | WO9001867 A (WIDEGREN LARS (SE)) 8 March 1990 | 1 |
| Y | * column 3, line 27 - line 43; figure 1 * | 2-5 |
| A | * figure 2 * | 6-10 |
Read it as: claim 1 is anticipated or obvious over this document alone; claims 2 to 5 are obvious when it is combined with another Y document in the report; claims 6 to 10 are only background. The passages listed are where the examiner found the closest disclosure, so start there. A report where every claim has an X against it and no claim is only A is a report where the independent claims will need to be amended. A report with only A documents points towards a positive opinion.
The search opinion
The search opinion reads like a first examination report. For each objection it must say which part of the application is deficient, which EPC requirement is not met and why, and every X or Y document cited against a claim should appear in it with a matching objection (Guidelines B-XI, 3.2.1). The usual subjects are novelty, inventive step (argued with the problem-solution approach), clarity and support under Article 84, and sufficiency of disclosure. It also covers formal points and any lack of unity.
Three points worth knowing. First, the examining division will normally follow the search opinion, but it can change its view after your reply or if a later top-up search finds an earlier European application (B-XI, 1.2). Second, the search division may suggest an acceptable amendment if there is a clear way out, but it is not obliged to (B-XI, 3.8). Third, a positive opinion needs no reply at all (B-XI, 3.9), though you may still file amendments.
No search opinion is issued if you requested examination, paid the examination fee and waived the Rule 70(2) invitation before the search report was sent. You get an examination communication under Article 94(3) instead (B-XI, 7). That is one of the ways to speed up EPO prosecution.
Incomplete searches: Rules 62a, 63 and 64
Before it searches, the EPO can ask you to narrow what it will search. Each invitation has a 2-month period, and each has consequences that last for the life of the application.
| Rule | Trigger | Your period | If you do not reply |
|---|---|---|---|
| Rule 62a | More than one independent claim in the same category without a Rule 43(2) exception | 2 months to say which independent claims to search | The first claim in each category is searched |
| Rule 63 | The claims are so unclear, broad or unsupported that no meaningful search is possible for some or all of them | 2 months to state the subject-matter to be searched | The search division decides; partial search report or declaration of no search |
| Rule 64 | Lack of unity: more than one invention claimed (Art. 82) | 2 months to pay a further search fee (€1,595) per extra invention | Only the invention first mentioned in the claims is searched |
Rule 62a: several independent claims in one category
Rule 62a(1) applies when the claims break Rule 43(2), which allows one independent claim per category unless they cover interrelated products, different uses, or alternatives that one claim cannot cover. You can name the claims to search, argue that an exception applies, or do both with the argument as your main request (Guidelines B-VIII, 4.2.2). Claims that depend only on an unsearched independent claim are not searched either. Our annotated Rule 62a page sets out the text of the rule next to the objections examiners raise most often.
Rule 63: no meaningful search possible
Rule 63 covers claims so broad, unclear or unsupported that a meaningful search of all or part of them is impossible: a claim defined by an unusual parameter no prior art uses, say, or so many claims that working out what is claimed becomes unduly burdensome. It cannot be used just because a search is hard (Guidelines B-VIII, 3). Reworded claims in your reply are treated as explanations, not amendments; you confirm them later when you reply to the EESR. If no reply arrives, the result is a partial search report or a declaration of no search, which then counts as the search report.
Why these invitations matter later
Further processing is ruled out for the Rule 62a, 63 and 64 periods (Rule 135(2)), so only re-establishment of rights, with its due-care test, rescues a missed reply. The search opinion will then ask you to limit the claims to what was searched (Rules 62a(2) and 63(3)), and Rule 137(5) bars amended claims directed to subject-matter left unsearched under those rules. Subject-matter dropped this way, or left unsearched because you did not pay further search fees under Rule 64 for a second invention, can still be pursued in a divisional application, at the cost of new filing, search and renewal fees.
Deadlines after the search report: Rules 70 and 70a
For a direct European application the clock does not start when the EESR arrives. It starts when the European Patent Bulletin mentions the publication of the search report, usually at the 18-month publication. From that date you have 6 months to request examination (Rule 70(1)), pay the designation fee (Rule 39(1)) and reply to the search opinion (Rule 70a(1)). The EPO tells you the date (Rule 69). For a first filing with the EESR at about month 6, that leaves well over a year between receiving the opinion and having to answer it.
| When | What is due | Law |
|---|---|---|
| About 6 months after filing | EESR sent: search report plus search opinion. No reply is due yet. | Rules 62, 65; OJ EPO 2025, A69 |
| 18 months from priority | Application published, normally with the search report (A1); if the search was late, the report follows separately (A3). | Art. 93, Rule 68 |
| 6 months after the Bulletin mentions the search report | Request examination and pay the examination fee, pay the designation fee, and reply to the search opinion. | Rules 39(1), 70(1), 70a(1) |
| Same day, if you paid the examination fee before the report arrived | Confirm you want to proceed (Rule 70(2) invitation) and reply to the search opinion. | Rules 70(2), 70a(2) |
| Euro-PCT with a supplementary search: 6 months from the Rule 70(2) communication | Confirm the request for examination and reply to the supplementary search opinion. | Rules 70(2), 70a(2) |
| 2 months after a loss-of-rights communication | Further processing if a deadline above was missed. | Art. 121, Rule 135(1) |
The Rule 70(2) case. If you paid the examination fee before the search report was sent, the EPO invites you to confirm that you want to proceed. For a direct application the period still runs 6 months from the Bulletin mention, and your reply to the search opinion counts as the confirmation (Guidelines C-II, 1.1). For a Euro-PCT application with a supplementary European search report, the 6 months run from the Rule 70(2) communication itself (C-II, 1.2.1). See our guide to the European regional phase for how that search is triggered.
If you miss it. The application is deemed withdrawn (Rule 70(3) and Rule 70a(3)) and the EPO sends a loss-of-rights communication. You then have 2 months to request further processing (Article 121, Rule 135(1)) by doing the missed act and paying the fee: €315 for a missed reply, or 50% of a fee paid late (RFees item 12).
Worked example
An applicant files a European first filing online on 3 March 2026 with 15 claims, and pays the filing fee and the €1,595 search fee within the month. The EESR arrives in August 2026: claim 1 has an X against it (D1), claims 2 to 4 have Y against them (D1 combined with D2), and claims 5 to 15 have only A documents. The search opinion says claim 1 lacks novelty over D1, claims 2 to 4 lack inventive step, and claim 5 would be inventive if made independent.
The application is published with the search report (A1) in September 2027, 18 months after filing. Suppose the Bulletin mentions publication on 8 September 2027. By 8 March 2028 the applicant must pay the examination fee (€2,010) and designation fee (€720) and reply to the opinion. The 12-month priority year ended on 3 March 2027, so the applicant already knew, before filing abroad, that claim 1 as drafted would not survive and that claim 5 was the fallback.
A good reply combines claims 1 and 5, shows the basis for the combination in the application as filed (Rule 137(4)), and explains in problem-solution terms why D1 plus D2 does not lead to the combined claim. If the applicant wants grant sooner, it can answer early instead of waiting until March 2028, and file a PACE request once the examining division takes over.
How to respond to the search opinion
- Map every X and Y. Build a claim chart of each independent claim against the X documents, feature by feature, using the passages the report cites. Do the same for the Y combinations.
- Decide: argue, amend or both. If the examiner misread a document, say so with the passage. If the X is real, find a feature in the description or dependent claims that the documents lack and that solves a technical problem.
- Stay within the application as filed. Amendments must not add matter (Article 123(2)). Identify each amendment and its basis (Rule 137(4)), or the examining division can ask you to within one month.
- Answer every objection. A bare request for oral proceedings, a consultation or a decision on the file, with no comment on the objections, is not a valid reply, and the application is deemed withdrawn (Guidelines B-XI, 8).
- Deal with limited searches. If a Rule 62a or 63 limitation applied, either limit the claims to what was searched or argue that the limitation was wrong. The examining division has the final word and can search further.
- Think about divisionals now. Subject-matter you delete may be worth keeping in a divisional. Avoid statements that could read as abandoning it (Guidelines C-IX, 1.3).
See the X documents before the EPO does
PatentAssist.ai does not draft replies to EPO search opinions. What it can do is cut the number of surprises in the EESR. Its prior-art search covers EPO, USPTO and Indian patent records, with AI search and classic field search, so you can look for likely X and Y documents before filing. The drafting workspace then writes EPO-format claims and a description with fallback features that can support an amendment later. See European patent search, prior art search and our guide to filing a European patent application.
More EPO guides
- How to file a European patent application
Direct or Euro-PCT filing, search, examination, grant and validation, with the EPO fees in force from 1 April 2026.
- Patent drawing requirements: USPTO, EPO and India
37 CFR 1.84, the EPO rules that replaced Rule 46 EPC, and Indian rule 15, compared side by side.
- How to write patent claims: USPTO, EPO and India
Claim structure and worked examples, then the claim rules and fees at the USPTO, the EPO and the Indian Patent Office, side by side.
- The Unitary Patent and the UPC, explained
The 18 countries covered, renewal fees, the UPC opt-out, and when classic validation is the better choice.
- EPO fees 2026: the full fee schedule
Every EPO fee in force from 1 April 2026, the 30% micro-entity reduction, PCT fees at the EPO and a fee calculator.
- How much does a European patent cost?
EPO fees to grant, translations, validation and renewals, with the EPO's Unitary Patent cost comparison and two worked examples.
- European patent validation: countries and deadlines
Translation rules and deadlines in all 40 EPC states, the London Agreement, extension and validation states, and the Unitary Patent.
- The problem-solution approach to inventive step at the EPO
Closest prior art, the objective technical problem and the could-would test, with a fully worked example and the usual mistakes.
- Software and AI patents in Europe
Computer-implemented and AI inventions at the EPO: Article 52, COMVIK, G 1/19, claim drafting, and the UK and US positions.
- European patent opposition at the EPO
The 9-month deadline and fee, the grounds, procedure and oral proceedings, appeal to the Boards, and how it compares with UPC revocation.
- Supplementary protection certificates (SPCs) in Europe
Who can get an SPC, how long it lasts, the filing deadline, the paediatric extension, the manufacturing waiver and the unitary SPC proposal.
- Entering the European phase from a PCT application
The 31-month deadline, Rule 159 acts and fees, the supplementary search, Rule 161, translations and a worked example.
- European divisional applications under Rule 36 EPC
When the parent is pending, fees by generation, back renewal fees, the Article 76 added-matter trap and timing.
- How to speed up EPO prosecution: PACE, PPH and waivers
PACE since February 2026, the Rule 70(2) and Rule 161 waivers, PPH with the USPTO, and fast Rule 71(3) approval.
- The European Patent Convention, annotated
Key EPC Articles and Rules explained one by one, from novelty and claims to Rule 71(3), with deadlines, fees and Enlarged Board case law.
- Types of patent searches, and which one you need
Patentability, freedom-to-operate, invalidity and landscape searches compared by purpose, timing, scope and deliverable.
- Patentability search: how to check novelty before you file
What counts as prior art under 35 U.S.C. 102 and Art. 54 EPC, the grace period gap, search steps and how to read results.
- Freedom-to-operate search in the US and Europe
In-force claims only, legal status checks at the USPTO, EPO and UPC, FTO opinions after Halo, and design-arounds.
- Invalidity search: prior art to challenge a patent
IPR, PGR, EPO opposition and UPC revocation deadlines, prior art dates, standards documents and claim charts.
- Patent landscape analysis, step by step
Building a CPC and keyword dataset, cleaning families and names, the metrics that matter and the 18-month publication lag.
- How to search Espacenet
Smart and Advanced search, field identifiers, proximity and truncation, CPC, INPADOC families, legal events and Global Dossier.
- Google Patents search guide
Search operators and fields, Boolean and proximity syntax, non-patent literature, and where Google Patents falls short of the official databases.
- The Cooperative Patent Classification (CPC), explained
How CPC symbols are built, CPC against IPC, the Y section, how to find the right class and how to search it in each database.
- Patent search Boolean operators and search strings
Boolean, proximity and truncation syntax compared across Patent Public Search, Espacenet, Google Patents and The Lens, with semantic search for contrast.
- The PCT application: timeline, fees and national phase
The international phase month by month, receiving Office and ISA fees in CHF, USD and EUR, national phase deadlines by office, and a deadline calculator.
- How much does a patent cost?
USPTO fees by entity size from filing to the last maintenance fee, what drives professional fees, EPO fees, and an estimator.
- How long does a patent last?
US utility and design terms, patent term adjustment and extension, terminal disclaimers, maintenance fee deadlines, Europe and India, with an expiry estimator.
- Can AI write a patent application?
What AI drafting does well and badly, the USPTO and EPO positions on AI tools, AI inventorship after 2025, and confidentiality.
European search reports: frequently asked questions
What is the difference between the European search report and the extended European search report?
The European search report lists the prior-art documents the EPO found, each with a category letter and the claims it relates to (Rule 61 EPC). The extended European search report (EESR) is that report plus the search opinion, a written opinion on whether the application and the invention seem to meet the EPC (Rule 62). The search report is published; the search opinion is not published with it (Rule 62(2)).
What do X, Y and A mean in a European search report?
X marks a document that on its own shows a claim is not new or not inventive. Y marks a document that destroys inventive step when combined with one or more other Y documents. A marks background art that does not prejudice novelty or inventive step. The letters P, O, E, D, T and L add information about dates, non-written disclosures, earlier patent applications, documents cited in your own application, theory and other reasons (Guidelines B-X, 9.2).
Do I have to respond to the extended European search report?
Yes, if the search opinion raises objections. Under Rule 70a EPC you must reply, with arguments, amendments or both, within the period for requesting examination: 6 months after the European Patent Bulletin mentions the publication of the search report. If you do not, the application is deemed withdrawn, although further processing is available. A reply is not required if the search opinion is positive.
What is the deadline to respond to a European search opinion?
Six months from the date the European Patent Bulletin mentions publication of the European search report (Rules 70(1) and 70a(1) EPC). If you paid the examination fee before the report was sent, the EPO sends a Rule 70(2) invitation and the reply is due within the period it sets, which runs to the same 6-month date. For a Euro-PCT application with a supplementary European search report, it is 6 months from the Rule 70(2) communication.
Is a request for oral proceedings a valid reply to the search opinion?
No. The Guidelines (B-XI, 8) say that a procedural request, such as for oral proceedings or a consultation, or a bare statement of disagreement, is not a valid response unless it comments on the objections raised. If that is all you file, the application is deemed withdrawn under Rule 70a(3).
What happens if I miss the 2-month deadline under Rule 62a or Rule 63?
The search goes ahead without your input: under Rule 62a the first independent claim in each category is searched, and under Rule 63 the search division decides what to search. Further processing is ruled out for these periods (Rule 135(2) EPC), though re-establishment of rights is possible. Later you will be asked to limit the claims to what was searched.
Can I amend the claims before I receive the European search report?
Not for a direct European application. Rule 137(1) EPC bars amendments before the search report is received, so the search and the search opinion are based on the application as filed. After receiving the report, you can amend of your own volition together with your reply to the search opinion (Rule 137(2)).
Sources: European Patent Convention, Rules 61, 62, 62a, 63, 64, 65, 69, 70, 70a, 135 and 137; EPO Guidelines for Examination (April 2026), B-X, B-XI, B-VIII and C-II, 1; Rules relating to Fees in force from 1 April 2026; OJ EPO 2025, A69; OJ EPO 2015, A94. Checked 26 October 2026. This guide is general information, not legal advice. Confirm deadlines for your application with a European patent attorney.