MPEP § 2304.02(d) — Adequate Written Description (Annotated Rules)

§2304.02(d) Adequate Written Description

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 2304.02(d), including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Adequate Written Description

This section addresses Adequate Written Description. Primary authority: 37 CFR 41.202. Contains: 2 requirements and 3 other statements.

Key Rules

Topic

Declaration of Interference

6 rules
StatutoryInformativeAlways
[mpep-2304-02-d-c61704f8233f216fc26906f3]
Specification Must Describe Invention Completely Where Interference Suggested
Note:
The specification must describe the invention completely if an interference has been suggested by the applicant.

(ii) Unpatentability for lack of written description under 35 U.S.C. 112 of an involved application claim where the applicant suggested, or could have suggested, an interference under § 41.202(a).

Jump to MPEP Source · 37 CFR 41.201Declaration of InterferenceInterference Proceedings (Pre-AIA)Disclosure Requirements
StatutoryInformativeAlways
[mpep-2304-02-d-e4e62cbc1b188d0bec58a822]
Interference Not Guaranteed for Desired Claim
Note:
An applicant cannot claim an interference simply because they desire one; the interfering claim must be allowable and supported by sufficient written description.

An applicant is not entitled to an interference simply because applicant wants one. The interfering claim must be allowable, particularly with respect to the written description supporting the interfering claim. However, the written description requirement does not demand, as a matter of law, actual examples or an actual reduction to practice. The written description requirement is met so long as the application or priority application sufficiently described the subject matter to a person skilled in the art. See Tas v. Beachy, 626 Fed. App'x. 999, 1005 (Fed. Cir. 2015) (nonprecedential).

Jump to MPEP Source · 37 CFR 41.202Declaration of InterferenceInterference Proceedings (Pre-AIA)
StatutoryRequiredAlways
[mpep-2304-02-d-46e95ac903468672db082c3a]
Interfering Claim Must Be Allowable with Sufficient Written Description
Note:
The interfering claim must be supported by adequate written description but does not require actual examples or reduction to practice.

An applicant is not entitled to an interference simply because applicant wants one. The interfering claim must be allowable, particularly with respect to the written description supporting the interfering claim. However, the written description requirement does not demand, as a matter of law, actual examples or an actual reduction to practice. The written description requirement is met so long as the application or priority application sufficiently described the subject matter to a person skilled in the art. See Tas v. Beachy, 626 Fed. App'x. 999, 1005 (Fed. Cir. 2015) (nonprecedential).

Jump to MPEP Source · 37 CFR 41.202Declaration of InterferenceInterference Proceedings (Pre-AIA)
StatutoryInformativeAlways
[mpep-2304-02-d-a7349bf99feabf9b0715bcea]
Specification Must Describe Invention Completely
Note:
The application or priority application must sufficiently describe the invention to a person skilled in the art, without requiring actual examples or reduction to practice.

An applicant is not entitled to an interference simply because applicant wants one. The interfering claim must be allowable, particularly with respect to the written description supporting the interfering claim. However, the written description requirement does not demand, as a matter of law, actual examples or an actual reduction to practice. The written description requirement is met so long as the application or priority application sufficiently described the subject matter to a person skilled in the art. See Tas v. Beachy, 626 Fed. App'x. 999, 1005 (Fed. Cir. 2015) (nonprecedential).

Jump to MPEP Source · 37 CFR 41.202Declaration of InterferenceInterference Proceedings (Pre-AIA)
StatutoryInformativeAlways
[mpep-2304-02-d-6c1f3be1e2d94e35490d8587]
Specification Must Describe Invention Adequately
Note:
The application must provide sufficient description for the invention to meet the written description requirement, even without actual examples or reduction to practice.

An applicant is not entitled to an interference simply because applicant wants one. The interfering claim must be allowable, particularly with respect to the written description supporting the interfering claim. However, the written description requirement does not demand, as a matter of law, actual examples or an actual reduction to practice. The written description requirement is met so long as the application or priority application sufficiently described the subject matter to a person skilled in the art. See Tas v. Beachy, 626 Fed. App'x. 999, 1005 (Fed. Cir. 2015) (nonprecedential).

Jump to MPEP Source · 37 CFR 41.202Declaration of InterferenceInterference Proceedings (Pre-AIA)
StatutoryInformativeAlways
[mpep-2304-02-d-3feb686504c9b597d1a28edb]
Inadequate Written Description Scrutinized Early in Interference
Note:
The rule emphasizes that inadequate written description in newly added or amended claims to provoke an interference is subject to heightened scrutiny early in the interference process.

Rather than copy a claim verbatim, the better practice is to add (or amend to create) a fully supported claim and then explain why, despite any apparent differences, the claims define the same invention. See 37 CFR 41.203(a). The problem of inadequate written description in claims added or amended to provoke an interference is so great that the issue has been singled out for heightened scrutiny early in the course of an interference. See 37 CFR 41.201, under “Threshold issue.” When an applicant copies a claim from another application or patent, the applicant’s claims are construed in view of the originating specification when the other party challenges the sufficiency of written description support. See Agilent Techs., Inc. v. Affymetrix, Inc., 567 F.3d 1366, 1375, 91 USPQ2d 1161, 1167 (Fed. Cir. 2009) (when a party challenges written description support for a copied claim in an interference, the originating disclosure provides the meaning of the pertinent claim language).

Jump to MPEP Source · 37 CFR 41.203(a)Declaration of InterferenceInterference Proceedings (Pre-AIA)PTAB Contested Case Procedures
Topic

PTAB Contested Case Procedures

2 rules
StatutoryInformativeAlways
[mpep-2304-02-d-1ac037d4d8c1f18cb9d1fc24]
Claims Copied from Other Patents Must Align with Original Disclosure
Note:
When an applicant copies a claim from another application or patent, the claims must be construed in light of the original disclosure to support written description requirements.

Rather than copy a claim verbatim, the better practice is to add (or amend to create) a fully supported claim and then explain why, despite any apparent differences, the claims define the same invention. See 37 CFR 41.203(a). The problem of inadequate written description in claims added or amended to provoke an interference is so great that the issue has been singled out for heightened scrutiny early in the course of an interference. See 37 CFR 41.201, under “Threshold issue.” When an applicant copies a claim from another application or patent, the applicant’s claims are construed in view of the originating specification when the other party challenges the sufficiency of written description support. See Agilent Techs., Inc. v. Affymetrix, Inc., 567 F.3d 1366, 1375, 91 USPQ2d 1161, 1167 (Fed. Cir. 2009) (when a party challenges written description support for a copied claim in an interference, the originating disclosure provides the meaning of the pertinent claim language).

Jump to MPEP Source · 37 CFR 41.203(a)PTAB Contested Case ProceduresDeclaration of InterferenceInterference Proceedings (Pre-AIA)
StatutoryInformativeAlways
[mpep-2304-02-d-2f1895f4604f4d1a47533737]
Copied Claims Require Originating Disclosure
Note:
When a party challenges written description support for copied claims in an interference, the originating disclosure provides the meaning of the pertinent claim language.

Rather than copy a claim verbatim, the better practice is to add (or amend to create) a fully supported claim and then explain why, despite any apparent differences, the claims define the same invention. See 37 CFR 41.203(a). The problem of inadequate written description in claims added or amended to provoke an interference is so great that the issue has been singled out for heightened scrutiny early in the course of an interference. See 37 CFR 41.201, under “Threshold issue.” When an applicant copies a claim from another application or patent, the applicant’s claims are construed in view of the originating specification when the other party challenges the sufficiency of written description support. See Agilent Techs., Inc. v. Affymetrix, Inc., 567 F.3d 1366, 1375, 91 USPQ2d 1161, 1167 (Fed. Cir. 2009) (when a party challenges written description support for a copied claim in an interference, the originating disclosure provides the meaning of the pertinent claim language).

Jump to MPEP Source · 37 CFR 41.203(a)PTAB Contested Case ProceduresDeclaration of InterferenceInterference Proceedings (Pre-AIA)
Topic

Reissue Patent Practice

1 rules
StatutoryRequiredAlways
[mpep-2304-02-d-98435f2335a9881fc0f19e31]
Claim Chart Required for Amended Claim
Note:
An applicant must provide a claim chart showing the written description for each claim in their specification if they add or amend a claim to provoke an interference.
(a) Applicant. An applicant, including a reissue applicant, may suggest an interference with another application or a patent. The suggestion must:
  • *****
  • (5) If a claim has been added or amended to provoke an interference, provide a claim chart showing the written description for each claim in the applicant’s specification, and
Jump to MPEP Source · 37 CFR 41.202Reissue Patent PracticeDeclaration of InterferenceInterference Proceedings (Pre-AIA)
Topic

Interference Proceedings (Pre-AIA)

1 rules
StatutoryInformativeAlways
[mpep-2304-02-d-25b4a67f396926b959d52933]
Claims Must Be Fully Supported by Description
Note:
When adding or amending claims, they must be fully supported by the description to define the same invention, addressing any apparent differences.

Rather than copy a claim verbatim, the better practice is to add (or amend to create) a fully supported claim and then explain why, despite any apparent differences, the claims define the same invention. See 37 CFR 41.203(a). The problem of inadequate written description in claims added or amended to provoke an interference is so great that the issue has been singled out for heightened scrutiny early in the course of an interference. See 37 CFR 41.201, under “Threshold issue.” When an applicant copies a claim from another application or patent, the applicant’s claims are construed in view of the originating specification when the other party challenges the sufficiency of written description support. See Agilent Techs., Inc. v. Affymetrix, Inc., 567 F.3d 1366, 1375, 91 USPQ2d 1161, 1167 (Fed. Cir. 2009) (when a party challenges written description support for a copied claim in an interference, the originating disclosure provides the meaning of the pertinent claim language).

Jump to MPEP Source · 37 CFR 41.203(a)Interference Proceedings (Pre-AIA)Declaration of InterferencePTAB Contested Case Procedures

Citations

Primary topicCitation
Declaration of Interference35 U.S.C. § 112
37 CFR § 41.2
Declaration of Interference
Interference Proceedings (Pre-AIA)
PTAB Contested Case Procedures
37 CFR § 41.201
Declaration of Interference37 CFR § 41.202(a)
Declaration of Interference
Interference Proceedings (Pre-AIA)
PTAB Contested Case Procedures
37 CFR § 41.203(a)

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2025-12-31