Proceedings guide

Ex Parte Reexamination

Updated By Wysebridge

Ex parte reexamination lets anyone, including the patent owner, ask the USPTO to re-examine an issued patent in light of prior patents or printed publications that raise a substantial new question of patentability. It can be requested at any time during the patent's enforceable life, the requester has limited participation, and no estoppel attaches to the requester.

Key Facts

Statute
35 U.S.C. §§ 301–307
Who can request
Anyone, including the patent owner
When
Any time the patent is enforceable
Basis
Substantial new question from patents or printed publications
Order decision
Within 3 months of the request
Requester role
The request, plus one reply
Estoppel
None
Handled by
Central Reexamination Unit
On this page
  1. The reexamination process
  2. Who may request, and when
  3. What the request must show
  4. How the process works
  5. Amendments and intervening rights
  6. Appeals
  7. Strengths and trade-offs

The reexamination process

  1. Any timeRequest filedPatents and printed publications, with an explanation of the substantial new question.
  2. Within 3 monthsOrder or denialThe Office decides whether a substantial new question exists.
  3. About 2 monthsPatent owner statementOptional; may include amendments.
  4. About 2 monthsRequester replyOnly if the owner filed a statement.
  5. OngoingExaminationEx parte between the owner and the examiner, with special dispatch.
  6. EndReexamination certificateClaims confirmed, cancelled or amended.

Ex parte reexamination has existed since 1981 and was not replaced by the America Invents Act. It remains a distinct tool because it is open to anyone, long-lived, and does not create IPR-style estoppel.

Who may request, and when

Any person, including the patent owner, may request reexamination of any claim at any time during the period of enforceability (35 U.S.C. § 302). The requester need not be sued or otherwise be in a dispute.

What the request must show

A request must identify prior patents or printed publications and explain how they raise a substantial new question of patentability (SNQ) for at least one claim (§§ 301–303). Other invalidity grounds, such as § 101 or § 112, cannot be the basis for an SNQ, although § 112 issues can arise once the claims are being amended.

How the process works

  1. Request filed with the required fee and claim charts.
  2. Order decision: the Office decides whether an SNQ exists, within three months of the request (§ 303).
  3. If ordered, the patent owner may file a statement and amendments; the requester may reply to that statement (§ 304).
  4. Examination proceeds like ordinary prosecution, handled by examiners in the Central Reexamination Unit, with “special dispatch” (§ 305). There are no discovery, depositions or oral hearings between the parties.
  5. Certificate issues, confirming, cancelling or amending claims (§ 307).

Amendments and intervening rights

The patent owner may amend claims or add new ones, but may not enlarge the scope of the claims (§ 305). Amended or new claims can create intervening rights for third parties who practiced the invention before the certificate.

Appeals

The patent owner may appeal to the Patent Trial and Appeal Board and then the Federal Circuit. A third-party requester has no corresponding appeal right in ex parte reexamination (§ 306).

Strengths and trade-offs

StrengthTrade-off
No standing needed; no statutory filing deadlinePrior art limited to patents and printed publications
No estoppel against the requesterRequester has little role after the request and reply
Lower cost than a trialOutcome can be amended claims, which may cut off past damages through intervening rights

Compare with inter partes review, and for owner-initiated options see supplemental examination and reissue.

Frequently Asked Questions

Is there a deadline to request ex parte reexamination?

Not in the way IPR has one. A request may be filed at any time during the enforceability of the patent (35 U.S.C. § 302).

Can the requester appeal?

In ex parte reexamination the patent owner, but not a third-party requester, may appeal an adverse decision to the Patent Trial and Appeal Board and then the Federal Circuit (35 U.S.C. § 306).

Primary Sources

  1. 35 U.S.C. §§ 301–307 (Prior art citations and ex parte reexamination)
  2. 37 C.F.R. §§ 1.510 and following (Ex parte reexamination)
  3. MPEP Chapter 2200 (Citation of prior art and ex parte reexamination)

Educational information; not legal advice. Statutes, rules and USPTO practice change. Confirm against the primary sources and consult a registered patent practitioner before acting. Disclaimer.