MPEP 2142: Prima Facie Obviousness

Answer in brief

MPEP 2142 places the initial burden on the examiner to establish a prima facie case of obviousness. If the examiner does, the burden shifts to the applicant to rebut it with argument or evidence. The examiner must avoid impermissible hindsight drawn from the applicant's own disclosure.

What MPEP 2142 covers

The prima facie case is the procedural tool for allocating burdens during examination.

The rejection must include an articulated reasoning with rational underpinning, not conclusory statements.
"Impermissible hindsight must be avoided and the legal conclusion must be reached on the basis of the facts gleaned from the prior art."
After rebuttal, the examiner weighs all the evidence anew rather than defending the original case.

How examiners use it

An Office action that states a combination is obvious without explaining why lacks a prima facie case, and applicants can say so.

On the patent bar

Know who has the burden at each stage and that the decision is made on the full record after rebuttal.

Read the full text

Official title: Legal Concept of Prima Facie Obviousness [R-01.2024].

Read MPEP 2142 in full on Wysebridge ↗

Or at the source: USPTO MPEP § 2142.

Sources for this entry

USPTO — MPEP § 2142 USPTO
Official text of this section, Ninth Edition, Revision 01.2024.
Wysebridge MPEP Center Wysebridge (publisher of this site)
The full MPEP (9th Ed., Rev. 01.2024) free to read, with Wysebridge's estimated patent bar weight for each chapter.

Practical guidance is original editorial content. Company-published figures are the company's own claims and are labeled as such.

Continue this reading path

MPEP 2143: The KSR Rationales for Obviousness MPEP 2145: Rebutting an Obviousness Rejection Impermissible Hindsight in the MPEP

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Cite or share this entry

MPEP.net. “MPEP 2142: Prima Facie Obviousness.” Wysebridge Reference. Content reviewed 9 November 2026.
https://mpep.net/mpep-2142/