Instead of filing application documents, the applicant can file a reference to a previously filed application according to Rule 40(1)(c). The previously filed application relied on for the reference does not need to be claimed as priority.

Details required on the date of filing [Rule 40(2); ]

According to Rule 40(2), in order to qualify for a date of filing, the applicant must indicate the following details on the filing date:

The previous application referred to may also be an application for a utility model.

Copy of the previously filed application [Rule 40(3); Rule 53(2); ]

The applicant must supply a copy of the previously filed application certified as correct by the authority with which that application was filed within two months of the filing date (Rule 40(3)). However, according to Rule 40(3), last sentence, this requirement is dispensed with where the previously filed application is already available to the EPO under the conditions specified by the President. According to the Notice from the EPO dated 14 September 2009, OJ EPO 2009, 486, a certified copy does not need to be filed where the previously filed application is a Euro-direct application or an international one filed with the EPO as receiving Office under the PCT. In all other cases, a certified copy of the previously filed application to which reference is made must be filed within the time limit under Rule 40(3).

Where the previously filed application referred to is the claimed priority application, only one certified copy needs to be filed in order to satisfy both the requirements relating to the filing date (Rule 40(3)) and those relating to the priority claim (Rule 53(1), see A‑III, 6.7).

For divisional applications filed by reference, see A‑IV, 1.3.1.

Translation of the previously filed application [Rule 40(3); ]

If the previously filed application is not in an official language of the EPO, the applicant must also file a translation into one of those languages within two months of the filing date (Rule 40(3)). If the translation of the previously filed application is already available to the EPO, a copy of this will be included in the file free of charge and the applicant will not need to file it (Rule 40(3)).

Note that where the previously filed application is in a language according to Art. 14(4) (an official language of a contracting state to the EPC), the application may qualify for a reduction of the filing fee, provided that the applicant is entitled according to Rule 6(3) in conjunction with Rule 6(4) to Rule 6(7) (see A‑X, 9.2.1 and A-X, 9.2.2). The reduction applies even in cases where the description is filed by reference to a previously filed application according to Rule 40(1)(c), where the previously filed application is in a language specified in Art. 14(4) but the claims are filed after the date of the filing in accordance with Rule 57(c) and Rule 58 and in an official language of the EPO. This is because the essential element for establishing a filing date (the provision of a description, see Rule 40(1)(c)) has been provided in a language giving rise to the entitlement to the reduction (see G 6/91, mutatis mutandis).

Applicants also have the option of indicating that they wish the claims of the previously filed application to take the place of claims in the application as filed. Such an indication must be made on the date of filing, preferably by crossing the appropriate box in the request for grant (EPO Form 1001). If this indication is made, then the claims of the previously filed application will form the basis for the search, and will satisfy the requirement of Rule 57(c), so that an invitation under Rule 58 to file claims later will not be issued.

If the applicants do not refer to the claims of the previously filed application, but only to the description and any drawings thereof, they may at the same time as filing the reference (i.e. on the date of filing), file a set of claims. If they do not do so, they will be invited by the EPO to file claims (see A‑III, 15).