EPO Patent Oppositions & Appeals

Best-in-class representation and guidance for oppositions and appeals at the European Patent Office (EPO), tailored for US patent owners.

We secure: your patents at the EPO

We help US-based clients navigate the EPO opposition and appeal process efficiently, strategically and cost-effectively.

You could be seeking to challenge third-party patent rights, thereby clearing the way for freedom to operate within Europe.

Alternatively, you may be defending your own patent during opposition proceedings initiated by a third party.

Listed as one of Europe’s leading patent law firms, we are perfectly placed to guide you through the entire process.

We bring deep expertise advising on complex oppositions and appeals across many specialist areas, including engineering, chemistry and materials, life sciences, and technology and media.

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A strategic, commercial approach to EPO oppositions

An EPO opposition is a procedure allowing a third party to challenge the validity of a granted European patent.

For US-based companies, opposition proceedings can be a powerful tool for securing freedom to operate in Europe. They are also a cost-effective alternative to litigation in national European courts, with a single procedure covering all EPC states.

Anyone can file an opposition to a patent within nine months of the date of the grant being published. Proceedings can lead to the patent being maintained as granted, amended or revoked.

Each case is different, which is why we always place EPO oppositions in their broader commercial context. Some may support a licensing or enforcement strategy, whilst others may be a make-or-break battle over a core technology.

Your case may also form part of a larger dispute involving the Unified Patent Court or a national court or office. We can help you coordinate across all of these, so each one works towards the same commercial goal.

Our sector knowledge
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One of ‘Europe’s leading patent law firms’

The EPO offers a centralised route to challenge a European patent across all contracting states, rather than having to fight multiple battles in national courts.

Whether you’re the patentee or the opponent, winning a case requires a meticulous approach, blending legal and advocacy skills.

  • Unrivalled expertise: Founded in 1975, our network of over 90 attorneys and 330 staff is one of Europe’s largest and most specialised.
  • End-to-end service: You will benefit from our support at every stage of proceedings, including assistance in preparing necessary documentation and evidence.
  • Thorough and creative: We’ve worked on many tough cases, including those involving multiple opponents. Our approach is analytical and, where needed, innovative – we’ll find the most suitable solutions, even those out of the ordinary.
  • Strategic oversight: We keep track of the bigger picture by tracking co-pending litigation and licence agreement negotiations, as well as drawing on in-house search expertise to monitor competitor activity and identify the most relevant prior art.
  • Industry recognition: As a law firm, we are routinely listed in patent rankings, including IAM 300, IAM 1000, IPStars, Legal 500, Chambers & Partners, ManagingIP and Financial Times.
Our awards & accreditations
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Your trusted European patent partner

We support US-based clients of all shapes and sizes with EPO oppositions and appeals, including start-ups, SMEs, large corporations and law firms.

With two US liaison offices and regular attorney travel, we work closely with founders, in-house counsel and C-suite executives to build a genuine understanding of your business and commercial goals.

We offer specialist docketing and search teams based across US time zones, alongside 24/7 advanced client portal access.

Our added value is acting as a seamless extension of your IP capabilities: a single point of contact and one-stop service for all your UK and European IP coordination and strategy.

Contact us

Extremely strong in opposition proceedings and providing strategic advice in pre-litigation scenarios.

Managing IP Research Insights

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Thank you for your opposition work, you are “killing it”. Your understanding of the technology is amazing and I am glad you are supporting us.

US based Chief IP Counsel

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(Catherine) Hanratty’s significant experience in examination, opposition and appeal proceedings at the EPO adds strategic depth to her versatile contributions.

IAM 1000 - 2025

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That's great news all, especially in current circumstances. Thanks everyone, especially Mark for overseeing this opposition from the start.

European Patent Attorney, US corporation

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FAQs: EPO patent oppositions and appeals

Our team brings a deep knowledge of EPO rules and procedures – message us if your query isn’t covered.

FAQs: Patent Opposition and Appeals

Discuss your patent opposition needs with an expert

Protect your patents and effectively challenge competitors at the EPO. Our support in oppositions and appeals ensures your rights are defended.

+44 [0] 141 307 8400info@murgitroyd.com
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