What is the European Patent Convention (EPC)?
The European Patent Convention (EPC) is an international treaty that created a centralized patent grant system in Europe, allowing applicants to seek protection across multiple European countries through a single application to the European Patent Office (EPO). The EPC was signed on October 5, 1973 in Munich and entered into force on October 7, 1977.
The founding contracting states were Belgium, West Germany, France, Luxembourg, the Netherlands, Switzerland, and the United Kingdom. As of 2026, the EPC has 40 contracting states; Moldova became the 40th on June 1, 2026.
The European Patent Organisation: structure and independence from the EU
The EPC established the European Patent Organisation, which operates through two organs: the European Patent Office (EPO) as its executive body, and the Administrative Council as its supervisory and limited legislative body. The organisation has its seat in Munich, Germany.
A critical point that trips up practitioners new to European prosecution: the European Patent Organisation is entirely independent from the European Union. Not all EPC contracting states are EU member states, and the EU itself is not a party to the EPC. EPC contracting states that are not EU members include the United Kingdom, Switzerland, Norway, Iceland, Albania, Liechtenstein, Moldova, Monaco, Montenegro, North Macedonia, San Marino, Serbia, and Turkey. This means a post-Brexit UK applicant or practitioner can still obtain a European patent covering EU member states, and conversely, EU membership does not determine EPC membership.
The EPC was revised at a diplomatic conference in November 2000, and the revised version, known as EPC 2000, entered into force on December 13, 2007. References to "EPC 2000" in prosecution documents refer to this revised text.
Languages of proceedings
The three official languages of EPC proceedings are English, French, and German; applications may be filed in any language but must be prosecuted in one of these three official languages, with a translation due within a prescribed period if the application was filed in another language. All three language versions of the EPC treaty text are equally authoritative, which matters when claim language or treaty provisions are interpreted.
What a European patent actually is
One of the most important conceptual points about the EPC is what a granted "European patent" is not. It is not a single, territorially unified right covering all EPC contracting states. A European patent is a bundle of essentially independent, nationally enforceable, and nationally revocable patents, one for each contracting state the applicant designated during prosecution.
Before grant, the application has unified legal status and is prosecuted centrally before the EPO. After grant, however, ownership, validity, and infringement of each national portion of the bundle are determined independently under the national law of each designated state. A German court ruling on infringement does not bind a French court for the same European patent, and a validity challenge in one country has no direct effect on the national portions in other countries (outside the centralized opposition procedure described below).
This structure has several practical consequences:
- Each national patent in the bundle can be independently challenged, licensed, assigned, or abandoned without affecting the others.
- Infringement litigation must be planned and pursued jurisdiction by jurisdiction.
- The cost of protecting a European patent across many states is substantially higher post-grant than the cost of obtaining it, because each country imposes its own renewal fees and (in some cases) translation requirements.
The extension and validation system
Beyond the 40 contracting states, the European patent system includes extension states and validation states: non-EPC countries that have bilateral agreements with the EPO allowing European patents to take effect on their territory. Current validation states include Morocco, Tunisia, Cambodia, Georgia, and Laos. Applicants seeking coverage in these territories must pay additional fees and follow the relevant bilateral agreement requirements, separate from standard EPC prosecution.
Patentability requirements under the EPC
Under EPC Article 52(1), European patents are granted for inventions that are novel, involve an inventive step, and are susceptible of industrial application. These three criteria broadly correspond to the novelty, non-obviousness, and utility requirements in US patent law, though the EPO applies them through its own case law and examination guidelines.
Excluded subject matter under Article 52(2): Discoveries, scientific theories, mathematical methods, aesthetic creations, schemes for performing mental acts, business schemes, computer programs, and presentations of information are excluded from patentability when claimed as such. The phrase "as such" is key: the EPO and the Boards of Appeal have developed a technical-effect doctrine allowing software and business-method claims that produce a technical effect beyond the normal interactions of software running on hardware to remain eligible. This doctrine differs significantly from both the US Section 101 framework and how national courts in EPC member states apply the same exclusions.
Additional exclusions under Article 53: Inventions contrary to public order or morality, plant and animal varieties and essentially biological processes for their production, and methods for surgical or therapeutic treatment or diagnostic methods practiced on humans or animals are excluded from patentability. Note that the exclusion of therapeutic methods does not extend to therapeutic products, which remain patentable.
The European patent grant procedure (overview)
European patent prosecution before the EPO follows a centralized sequence:
| Stage | What happens |
|---|---|
| Filing | Application received by the EPO (or a national office of an EPC state), formality examination |
| Search | EPO Search Division prepares a European Search Report identifying relevant prior art |
| Publication | Application published; search report typically included |
| Substantive examination | EPO Examination Division assesses novelty, inventive step, industrial applicability, and formal requirements |
| Grant | EPO issues the decision to grant; the central prosecution phase ends |
| National validation | Patent holder validates the patent in each designated state |
Post-grant opposition
After the EPO grants a European patent, any person may file a centralized opposition at the EPO challenging the grant. The opposition is handled by the EPO's Opposition Division and can result in the patent being revoked or maintained only in amended form, with that outcome applying uniformly across all designated states. This centralized mechanism is strategically significant: a single EPO opposition, if successful, can unravel coverage in all designated countries simultaneously, which is far more efficient for challengers than litigating validity in each national court.
Validation after grant
After the EPO grants a European patent, the patent holder must validate the patent in each designated contracting state by paying national fees and, in some states, filing a translation of the patent. Failure to validate within the applicable period causes the patent to lapse in that state, providing no protection there regardless of the EPO grant.
The London Agreement, which entered into force on May 1, 2008, significantly reduces the number of translations required when validating in the contracting states that joined it. States party to the London Agreement either accept the EPO grant language without translation or require only that the claims (not the full description) be translated into their official language. Practitioners should check on a state-by-state basis which states require translations and in what form.
The Unitary Patent: a distinct option
Practitioners should distinguish the traditional bundle European patent from the Unitary Patent, a separate legal instrument. The Unitary Patent became available on June 1, 2023, and provides uniform protection across participating EU member states through a single object of property administered by the Unified Patent Court, with a single renewal fee.
The Unitary Patent is not an alternative to EPC prosecution; it is an optional follow-on to a standard EPO grant. After the EPO issues the grant decision, the applicant can request unitary effect. The Unitary Patent does not, however, cover non-EU EPC contracting states such as Switzerland, Norway, or the United Kingdom. Applicants targeting those territories must still validate nationally in each of them, regardless of whether they also request a Unitary Patent for EU member states.
EPC and PCT
The EPC is separate from the Patent Cooperation Treaty (PCT), but the two systems work together. PCT international applications may enter the European regional phase at the EPO, allowing applicants who filed a PCT application to pursue European patent protection without filing a separate initial application directly with the EPO. For applicants seeking European coverage as part of a multi-country PCT strategy, the regional phase entry at the EPO is the standard pathway into full EPC prosecution.
Practical notes for practitioners
- EPC is not the EU. Applicants and practitioners from non-EU jurisdictions, including the UK post-Brexit, can obtain European patents covering EU member states without issue. Conversely, EU membership does not determine EPC membership; advise clients not to conflate the two.
- The bundle structure demands careful validation planning. A granted European patent provides no automatic protection anywhere. Each national patent in the bundle activates only after proper validation, including payment of national fees and any required translation. Budget these costs for every target jurisdiction before filing.
- Software claim strategy differs from US practice. The EPO's technical-effect doctrine for Article 52(2) exclusions produces different outcomes from US Section 101 doctrine and from how national courts in EPC states apply the same exclusions. Coordinate strategy carefully with European associates.
- Centralized opposition is asymmetric for challengers. A single EPO opposition can revoke or amend coverage in every designated state at once. For third parties seeking freedom to operate, this centralized mechanism offers significant leverage at relatively low cost compared to multi-jurisdictional national litigation.
- The Unitary Patent adds a new decision point at grant. Applicants who receive an EPO grant now must decide whether to request unitary effect (for EU coverage under one renewal fee) alongside or instead of national validation. Non-EU EPC states require separate national validation regardless of that choice.
- Verify translation requirements state by state. The London Agreement reduced but did not eliminate translation costs. Check which states are London Agreement parties and what they require before budgeting validation.