MPEP 2304.04(b)
Requiring a Claim

Ninth Edition of the MPEP, Revision 10.2019, Last Revised in June 2020

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2304.04(b)    Requiring a Claim [R-10.2019]

35 U.S.C. 132 Notice of rejection; reexamination.

  • (a) Whenever, on examination, any claim for a patent is rejected, or any objection or requirement made, the Director shall notify the applicant thereof, stating the reasons for such rejection, or objection or requirement, together with such information and references as may be useful in judging of the propriety of continuing the prosecution of his application; and if after receiving such notice, the applicant persists in his claim for a patent, with or without amendment, the application shall be reexamined. No amendment shall introduce new matter into the disclosure of the invention.


The examiner may, pursuant to 35 U.S.C. 132(a), require an applicant to add a claim that would interfere with the claim of another application or patent. For example, the requirement may be made to obtain a clearer definition of the interfering subject matter or to establish whether the applicant will pursue claims to the interfering subject matter. When the requirement is based on a published application with allowed claims or a patent, the examiner must identify the published application or the patent in making the requirement.

Given the cost and complexity of interferences, a requirement to add a claim under 37 CFR 41.202(c) should not be lightly made. Before making the requirement, the examiner should consult with an Interference Practice Specialist (IPS). The following principles should guide the examiner in exercising discretion to make this requirement:

  • (A) An interference should generally not be suggested if examination of the application is not otherwise completed.
  • (B) The required claim must not encompass prior art or otherwise be barred.
  • (C) The application must provide adequate support under 35 U.S.C. 112(a) for the subject matter of the required claim.
  • (D) A claim should not be required when the applicant expressly states that the commonly described subject matter is not the applicant’s invention.
  • (E) A claim based on a claim from a published application should not be required unless the claim from the published application has been allowed.

Example 1

A patent is pre-AIA 35 U.S.C. 102(b) prior art against any possible interfering claim. No interfering claim should be required.

Example 2

The patent issued more than one year ago and the applicant did not previously have a claim to the same subject matter. Any added claim would most likely be time barred under pre-AIA 35 U.S.C. 135(b)(1). No interfering claim should be required.

Example 3

An application describes work that it attributes to another who is not named as an inventor in the application ("other inventor"), but also describes and claims an improvement to that work. The other inventor has received a patent for the original work. The application may in some sense have 35 U.S.C. 112(a) support for an interfering claim to the other inventor’s work. Nevertheless, the application expressly states that the commonly described subject matter is not the invention of the inventor named in the application. No interfering claim should be required.

Example 4

An application has support for both a generic claim G and a species claim G1. The applicant only claims the genus G. A patent discloses and claims only G1. Under the facts of this example, there is no evidence that genus G would have rendered the species G1 obvious. If for some reason the patent is not available as a reference against the application, the examiner may require the applicant to add a claim to species G1 after consulting with an IPS.

Example 5

Published application H and application I both support a claim to H1. Published application H contains a claim to H1, but application I does not. The claim to H1 in the published application is under rejection. Applicant I should not ordinarily be required to add the claim.

Form paragraph 23.04 may be used to require applicant to add a claim to provoke interference.

¶ 23.04    Requiring Applicant to Add Claim to Provoke Interference

The following allowable claim from [1] is required to be added for the purpose of an interference:


The claim must be copied exactly.

Applicant is given TWO (2) MONTHS from the mailing date of this communication to add the claim. Refusal to add a required claim will operate as a concession of priority for the subject matter of the required claim, but will not result in abandonment of this application. See 37 CFR 41.202(c) and MPEP § 2304.04(b). EXTENSIONS OF THIS TIME PERIOD MAY BE GRANTED UNDER 37 CFR 1.136(a) but in no case can any extension carry the date for reply to this letter beyond the maximum period of SIX MONTHS set by statute (35 U.S.C. 133 ). If the interference would be with a patent, applicant must also comply with 37 CFR 41.202(a)(2) to (a)(6).

Examiner Note:

1. In bracket 1, insert the published application number if the claim is an allowed claim from a U.S. application publication or the patent number if the claim is from a U.S. patent.

2. In bracket 2, insert the claim which applicant is required to add to provoke an interference.


If required to add a claim under 37 CFR 41.202(c), the applicant must do so. Refusal to add a required claim will operate as a concession of priority for the subject matter of the required claim. The applicant would then be barred from claiming, not only the subject matter of the required claim, but any subject matter that would have been anticipated or rendered obvious if the required claim were treated as prior art. See In re Ogiue, 517 F.2d 1382, 1390, 186 USPQ 227, 235 (CCPA 1975).

While complying with the requirement to add a claim, an applicant may also express disagreement with the requirement several ways, including:

  • (A) Identifying a claim already in its application, or another of its applications, that provides a basis for the proposed interference;
  • (B) Adding an alternative claim and explaining why it would provide a better basis for the proposed interference (such as having better support in the applicant’s disclosure); or
  • (C) Explaining why the required claim is not patentable to the applicant.

The examiner may withdraw the requirement if persuaded by the reasons the applicant offers.