5.5.3Form and content of the notice of opposition 

5.5.003Notice of opposition must be filed within the opposition period in a reasoned statement. That means that the opponent must state at least one ground for opposition under Article 100 and indicate the facts, evidence and arguments presented in support of the ground(s). Otherwise the notice of opposition will be rejected as inadmissible. It is advisable to use the EPO opposition form (EPO Form 2300), which provides all the information needed to ensure that an opposition is admissible. This form is integrated in the permitted electronic filing tools. It is also available on the EPO website (epo.org).

Notice of opposition may be filed electronically via the EPO Online Filing software or EPO Online Filing 2.0, but not via the EPO Web-Form Filing service (see points 4.4.001-4.4.006). It may also be filed by post or by hand.