The European Patent Office (EPO) opposition procedure offers third parties an opportunity to attack a European patent centrally at the EPO for a limited period after grant. The option to attack a European patent centrally after grant is usually a much more appealing alternative to attacking it through the local procedures on a country-by-country basis after it has nationalized. Attacking a patent on a country-by-country basis can be more time consuming and costly, and the results may vary in different jurisdictions.

Approximately 3,000 patents are opposed at the EPO every year (about 5% of the total number of granted patents). The popularity of the proceeding is in part supported by the success rate. Historically, about one-third of the cases result in complete revocation of the patent, and about one-third result in some reduction of claim scope. Recently, more cases are being amended to avoid revocation. Even if a challenger is unsuccessful in the first instance, the statistics support further pursing the opposition through appeal. About 50% of appeals against Opposition Division decisions are successful at the Boards of Appeal.

Another appealing aspect of the procedure is that it provides multiple grounds for opposition, including patentability, such as novelty and inventive step (on the basis of any available prior art, including prior public use), excluded subject matter, and industrial application; insufficient disclosure/teaching; and added subject matter during prosecution. The cost is also appealing when compared to litigation, since the procedure is essentially a documentary one which usually culminates in a one-day oral hearing. However, because of the limited window of nine months from grant of a European patent to file an opposition, a possible opponent must closely monitor the patent landscape. Therefore, any effective opposition program or practice must also effectively map and monitor competitors' patenting activities.

Finnegan's European patent attorneys are experienced in all aspects of complex and high-value oppositions. We regularly defend clients' patents, including against multiple opponents, while also helping clients establish freedom-to-operate by challenging patents in the EPO before both the Opposition Division and the Board of Appeals. We represent clients in a variety of industry sectors and the broad technical expertise of our attorneys allows our opposition teams to draw on experience in just about every technical field. After years of assisting clients in opposition proceedings, Finnegan attorneys understand how to navigate the complex procedures established by the EPO and how to take best advantage of the rules to benefit each client’s unique situation.

Finnegan's extensive patent litigation experience combined with our knowledge of U.S. Patent and Trademark Office (USPTO) post-grant procedures also provides us with an educated and unique perspective on how best to coordinate oppositions within a global context. Drawing on our experience in multi-jurisdictional coordination, we are not only able to maximize efficiencies, but we are also able to intelligently use the optimal combination of procedures and approaches to obtain the best results for each individual client.


Cupitt, Philip
Partner, European Patent Attorney
+44 (0)20 7864 2811

Ford, Hazel
Partner, European Patent Attorney
+ 44 (0) 20 7864 2820

Hyden, Martin
Partner, European Patent Attorney
+44 (0)20 7864 2810

Wall, Leythem
Partner, European Patent Attorney
+44 (0)20 7864 2814