35 U.S.C. · Part III · Chapter 29, Remedies for infringement of patent, and other actions

35 U.S.C. 282: Presumption of validity; defenses

In plain English

Every claim of an issued patent is presumed valid, independently of the other claims. A dependent claim stays presumed valid even if the claim it depends on is held invalid. The party asserting invalidity carries the burden of proof (section 282(a)), and in court that burden is clear and convincing evidence.

Section 282(b) lists the defenses that must be pleaded in any action involving validity or infringement: noninfringement, absence of liability or unenforceability; invalidity on any ground in Part II as a condition for patentability (sections 101, 102 and 103); invalidity for failure to meet section 112 or section 251; and any other defense the title provides, such as the prior commercial use defense in section 273.

Section 282(c) requires the party challenging validity or asserting noninfringement to give the patentee written notice, at least 30 days before trial, of the patents, publications and people it will rely on as prior art. Otherwise that evidence can be admitted only on terms the court sets.

Annotation by Raj Sutariya, Co-founder, PatentAssist.ai. General information, not legal advice; the statute below governs.

AIA and pre-AIA

The AIA added the exception in section 282(b)(3)(A): failure to disclose the best mode is no longer a basis for canceling a claim or holding it invalid or otherwise unenforceable. It applies to proceedings commenced on or after September 16, 2011. Best mode remains a requirement of section 112(a) during examination.

Text of 35 U.S.C. 282

Current text, quoted from the official United States Code.

(a) In General.— A patent shall be presumed valid. Each claim of a patent (whether in independent, dependent, or multiple dependent form) shall be presumed valid independently of the validity of other claims; dependent or multiple dependent claims shall be presumed valid even though dependent upon an invalid claim. The burden of establishing invalidity of a patent or any claim thereof shall rest on the party asserting such invalidity.
(b) Defenses.— The following shall be defenses in any action involving the validity or infringement of a patent and shall be pleaded:
(1) Noninfringement, absence of liability for infringement or unenforceability.
(2) Invalidity of the patent or any claim in suit on any ground specified in part II as a condition for patentability.
(3) Invalidity of the patent or any claim in suit for failure to comply with—
(A) any requirement of section 112, except that the failure to disclose the best mode shall not be a basis on which any claim of a patent may be canceled or held invalid or otherwise unenforceable; or
(B) any requirement of section 251.
(4) Any other fact or act made a defense by this title.
(c) Notice of Actions; Actions During Extension of Patent Term.— In an action involving the validity or infringement of a patent the party asserting invalidity or noninfringement shall give notice in the pleadings or otherwise in writing to the adverse party at least thirty days before the trial, of the country, number, date, and name of the patentee of any patent, the title, date, and page numbers of any publication to be relied upon as anticipation of the patent in suit or, except in actions in the United States Court of Federal Claims, as showing the state of the art, and the name and address of any person who may be relied upon as the prior inventor or as having prior knowledge of or as having previously used or offered for sale the invention of the patent in suit. In the absence of such notice proof of the said matters may not be made at the trial except on such terms as the court requires. Invalidity of the extension of a patent term or any portion thereof under section 154(b) or 156 because of the material failure—
(1) by the applicant for the extension, or
(2) by the Director,
to comply with the requirements of such section shall be a defense in any action involving the infringement of a patent during the period of the extension of its term and shall be pleaded. A due diligence determination under section 156(d)(2) is not subject to review in such an action.

Key cases

Microsoft Corp. v. i4i Ltd. Partnership, 564 U.S. 91 (2011). Invalidity must be proved by clear and convincing evidence, even when the challenger relies on prior art the USPTO never considered. The jury may be instructed to consider that the USPTO did not have the evidence before it.

Practical notes

The presumption is a court rule, not a PTAB rule. In inter partes review and post-grant review the petitioner proves unpatentability by a preponderance of the evidence (sections 316(e) and 326(e)), and there is no presumption of validity. That difference is one reason accused infringers file at the PTAB.

Because each claim is presumed valid on its own, a well-built set of dependent claims with genuinely different fallback features is the cheapest insurance a patent owner can buy at the drafting stage.

Accused infringers should collect prior art early. The 30-day notice in section 282(c) is a minimum; scheduling orders in patent cases usually require invalidity contentions much sooner.

Related rules and guidance

37 CFR: No USPTO rules implement this section; it is applied by the courts.
MPEP: 2165