page_title: Opposition procedure before the European Patent Office
section_title: Substantive examination
hierarchical_section_title: Opposition procedure before the European Patent Office / Substantive examination
caption_attribution_description: Deutsch: Deutschland, Bayern, München, Europäisches Patentamt, Hackerbrücke English: Germany, Bavaria, Munich, European Patent Office, Kurt-Haertel-Passage (view from the Hackerbrücke side of the walkway)
context_page_description: The opposition procedure before the European Patent Office is a post-grant, contentious, inter partes, administrative procedure intended to allow any European patent to be centrally opposed. European patents granted by the EPO under the European Patent Convention may be opposed by any person from the public. This happens often when some prior art was not found during the grant procedure, but was only known by third parties.
  An opposition can only be based on a limited number of grounds, i.e. on the grounds that the subject-matter of the patent is not patentable, that the invention is insufficiently disclosed, or that the content of the patent extends beyond the content of the application as filed. The notice of opposition to a European patent must be filed in writing at the EPO, along with the payment of an opposition fee, within nine months from the publication of the mention of the grant of the patent in the European Patent Bulletin. Opposition Divisions of the EPO are responsible for the examination of oppositions. The opposition procedure may involve multiple opponents. According to the EPO, a European patent was once opposed by a record number of 27 opponents.
context_section_description: If the opposition is admissible, the grounds for opposition are examined as to their merits. The patent proprietor has also the opportunity to reply to the grounds of opposition developed by the opponent. Arguments and, to a certain extent, amendments may be filed in reply by the patent proprietor.
  In view of the grounds of opposition, and in view for instance of a prior art document introduced into the proceedings by the opponent, the patent proprietor may amend the patent, i.e. the description, claims and drawings of the patent, although amendments may not be filed of right at any stage during the opposition proceedings. The patent proprietor is master of its own patent in that the decision to amend or not, and how to amend the patent, is a decision of the patent proprietor alone (although the Opposition Division or the opponent may apply pressure to have amendments made). The patent, however, may not be amended in such a manner that the amendment would lead to an extension of the protection conferred by the patent.
  If amendments are made to the patent during the opposition proceedings, the patent (and the invention to which it relates) must meet the requirements of the EPC. These requirements notably include the requirements of support in the description and clarity (Article 84 EPC), even though those are not listed as grounds of opposition in Article 100 EPC. However, the requirements to be met by the amended patent do not include the requirement of unity of invention (because divisionals cannot be filed after grant).
  During the opposition, oral proceedings may take place at the request of the EPO or at the request of any party to the proceedings, i.e. the patentee or an opponent. The oral proceedings are held before the Opposition Division itself. They are held in Munich, the Hague or Berlin, and are public unless very particular circumstances apply. This contrasts with oral proceedings held before an Examining Division, which are not public. The list of public oral proceedings in opposition before the EPO is available on its web site. The right to oral proceedings is a specific and codified part of the procedural right to be heard. A decision is often taken at the end of the oral proceedings.
caption: Buildings of the EPO in Munich where some oppositions are handled.
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