G4/19 – EPO confirms their position on double patenting


Double patenting, as the name suggests, refers to obtaining two or more patents for the same subject-matter.  Double patenting applies to two or more patent applications filed by the same applicant, claiming the same subject-matter.

In Europe, double patenting may occur:

(1) when an applicant files two European applications on the same day, claiming the same subject-matter

(2) when parent and divisional European applications claim the same subject-matter, or

(3) when a European application claims priority to another European patent or European patent application, and both the European priority application and the European priority claiming application claim the same subject-matter.

Although examiners at the European Patent Office (EPO) have been raising double patenting objections for many years, there is no legal basis for such an objection.

The EPO Guidelines Chapter G.IV.5.4 states that the EPC does not deal explicitly with the case of co-pending European applications of the same effective date filed by the same applicant. However, it is an accepted principle in most patent systems that two patents cannot be granted to the same applicant for one invention.

The Enlarged Board of Appeal had previously made non-binding statements regarding the issue of double patenting in G1/05 and G1/06 and concluded that an applicant has no legitimate interest in obtaining two patents for the same application.  However, these cases related to divisional applications claiming the same subject-matter as a parent patent, i.e. the situation (2) of double patenting discussed above.  Therefore, it was not clear whether these comments also applied to the other situations (1) and (3) of double patenting outlined above.

Decision G4/19 issued on 22 June 2021 now provides the legal basis for, a double patenting objection for each type of double patenting at the EPO.

Background of the case

European patent application 10718590.2 (EP’590) claimed priority to another, subsequently granted, European patent application 09159932.4 (EP’932).

EP’590 was refused on the grounds of double patenting.  The examining division found that claim 1 of EP’590 was directed to subject-matter which was already claimed in EP’932 (the granted European patent which EP’590 was claiming priority to).  This is a situation of internal priority; where one European patent or European patent application serves as the priority application for another European patent application.

The examining division refused EP’590 under Articles 97(2) and 125 EPC.

Article 97(2) EPC recites:

(2) If the Examining Division is of the opinion that the European patent application or the invention to which it relates does not meet the requirements of this Convention, it shall refuse the application unless this Convention provides for a different legal consequence.

This article was used to refuse EP’590 on the grounds of double patenting.

Article 125 EPC recites:

 In the absence of procedural provisions in this Convention, the European Patent Office shall take into account the principles of procedural law generally recognised in the Contracting States.

This article was used to argue that EP’590 could not claim the same subject-matter as its priority document EP’932 even though there was no procedural provisions in the EPC prohibiting double patenting because the prohibition of double patenting was generally recognised in the Contracting States.

The applicant appealed the examination decision, arguing that the prohibition of double patenting did not apply in a situation of internal priority, because the comments made in G1/05 and G1/06 only related to divisional applications. The applicant also argued that Article 125 EPC could not provide proper legal basis for a double patenting objection because double patenting related to substantive law, and not procedural law, which was referred to in Article 125 EPC.

The Technical Board of Appeal in T 318/14 questioned whether Article 125 EPC provided suitable legal basis for double patenting and therefore referred three questions concerning the legal basis of the EPC for refusing an application on the grounds of double patenting to the Enlarged Board of Appeal.


In G4/19, the Enlarged Board of Appeal confirmed that Article 125 EPC does provide the legal basis for a double patenting objection and that the conditions for double patenting are the same for each type of double patenting.

 The decision states:

A European patent application can be refused under Articles 97(2) and 125 EPC if it claims the same subject matter as a European patent which has been granted to the same applicant and does not form part of the state of the art pursuant to Article 54(2) and (3) EPC.

The application can be refused on that legal basis, irrespective of whether it

a) was filed on the same date as, or
b) is an earlier application or a divisional application (Article 76(1) EPC) in respect of, or
c) claims the same priority (Article 88 EPC) as the European patent application leading to the European patent already granted.

The Enlarged Board of Appeal’s reasoning in G4/19 relied on their interpretation of Article 125 EPC in light of the travaux preparatoires (the preparatory documents used in the formation of the EPC) which were used as a supplementary means of interpretation.

The decision states that double patenting was considered in the travaux preparatoires, in the context of Article 125 EPC and the majority agreed that the European Patent Office should prohibit double patenting by a direct application of Article 125 EPC.

The Enlarged Board of Appeal state that the term “procedural provisions” in Article 125 EPC may extend to provisions requiring a substantive examination of the subject-matter claimed.  It decided that the prohibition on double patenting is generally recognised in the Contracting States and therefore constitutes a principle of procedural law within the meaning of Article 125 EPC.

Practice points

This decision now provides the EPO with the legal basis to raise a double patenting objection, despite there being no explicit prohibition for double patenting in the EPC.

However, there are still questions to be asked about what constitutes “the same-subject-matter” in the context of a double patenting objection.  For example, the EPO Guidelines state that the applicant can pursue protection for a preferred embodiment in a parent application and pursue the general teaching in a divisional application.  However, determining what is the “same subject-matter” is subjective.  The issue of the “same subject-matter” were not discussed in G4/19 because the claims of the application and the granted patent were identical.  Therefore, no further clarity has been provided on this point.

In addition, the question of the “same applicant” in the context of double patenting was not addressed in G4/19.  We may see future cases that argue a double patenting objection can be avoided if the European patent application is assigned to a different applicant before grant.

Therefore, we are likely to see more appeals and referrals to the Enlarged Board of Appeal to provide more clarity on these requirements for double patenting that were not covered in G4/19.