Up to nine months after publication of the mention of grant of a European patent, anyone (except the proprietor, who is not allowed to oppose his own patent) may file a notice of opposition to the patent with the EPO.

This person is called the opponent.

The name format for an opponent who is a person consists of the surname followed by the first name. It should be entered within quotation marks.

You cannot use apostrophes ('), hyphens (-) or slashes (/). Use blank spaces instead. Diacritical characters (umlauts and accents) are not allowed, so please enter your search terms without them.

Opponent names are not searchable in documents published in other alphabets (Cyrillic, Greek, Japanese, etc.).

For example, we recommend that you search for Muller or Mueller in order to retrieve all spellings (Muller/Müller/Mueller).

You can search for oppositions filed in a specific technical field (enter an IPC symbol) or by a specific applicant by combining your query with the code 01 in the "Opponent" search field.