Parker, Acting Commissioner of Patents and Trademarks v. Flook
The Court ruled that an invention that departs from the prior art only in its use of a mathematical algorithm is patent eligible only if there is some other "inventive concept in its application."
437 U.S. 584 · No. 77-642 · 1977 term · Burger Court
Decided Jun 22, 1978 · argued Apr 25, 1978
Economic activity · Patents and copyrights: patentability of computer processes
Majority opinion: John Stevens
The voteMajorityDissent
6–36 in the majority, 3 in dissent
3 dissents (6–3)
Reversed. Parker, Acting Commissioner of Patents and Trademarks won.
What this ruling means
Reversed: the Supreme Court overturned the decision of the U.S. Court of Customs and Patent Appeals, and its own ruling ends the case.
Parker, Acting Commissioner of Patents and Trademarks was the petitioner, the side that asked the Supreme Court to review the case. “Won” means the Court gave that side the result it asked for.
From the Supreme Court Database. A justice who agreed with the result but not the reasoning counts in the majority.
Summary
The opening of the case’s Wikipedia article: what the case was about and what the Court held.
Parker v. Flook, 437 U.S. 584 (1978), was a 1978 United States Supreme Court decision that ruled that an invention that departs from the prior art only in its use of a mathematical algorithm is patent eligible only if there is some other "inventive concept in its application." The algorithm itself must be considered as if it were part of the prior art, and the claim must be considered as a whole. The exact quotation from the majority opinion is:
"Respondent’s process is unpatentable under §101, not because it contains a mathematical algorithm as one component, but because once that algorithm is assumed to be within the prior art, the application, considered as a whole, contains no patentable invention." "The fact that the algorithm may not have actually been known previously and that, when taken in combination with other claim elements, it might produce an invention that is novel
and nonobvious, plays no part in the analysis."
The case was argued on April 25, 1978 and was decided June 22, 1978. This case is the second member of the Supreme Court's patent-eligibility trilogy.
Data notes
The text is Wikipedia’s (CC BY-SA 4.0), matched to the case by its citation, docket number or name and year, and is not checked against the opinion. The site keeps the article’s opening section, ending on its last full sentence. The one-sentence summary under the title is the Decisions list’s: Wikipedia’s own ruling sentence, or, tagged “AI-written”, one Claude wrote from this opening.
How the justices voted
Each justice who took part, placed by their Martin–Quinn ideology score for the 1977 term. Filled: the 6 in the majority. Hollow: the 3 in dissent. Colour is the party of the president who appointed them.
Majority(6)
John StevensWrote the majority opinion
Thurgood MarshallJoined the majority
William BrennanJoined the majority
Byron WhiteJoined the majority
Harry BlackmunJoined the majority
Lewis PowellJoined the majority
Dissent(3)
Potter StewartWrote a dissent
Warren BurgerJoined a dissent
William RehnquistJoined a dissent
Data notes
Each justice’s vote and what they wrote are from the justice-centered file of the Supreme Court Database. “Wrote a concurrence” means the justice sided with the majority and wrote separately; a justice who dissented in part is counted on the side they took overall. A justice who wrote nothing is listed as joining their side.
Positions are each justice’s Martin–Quinn score for the case’s term, the same scores as the Ideology page: negative is more liberal, positive more conservative. A score sums up a justice’s votes across the whole term, so it says where they usually sit, not why they voted as they did here. The median line is the Court’s median justice that term.
The parties
Who brought the case to the Court, who answered it, and how it got there.
- Petitioner
- Parker, Acting Commissioner of Patents and TrademarksPatent Office, or Commissioner of, or Board of Appeals
- Respondent
- FlookInventor, patent assigner, trademark owner or holder
- Reached the Court by
- Certiorari (the Court chose to hear it)
Data notes
The names are the two sides of the case’s title. The description under each is the Supreme Court Database’s category for that party, in its own wording. The petitioner is the side that asked the Supreme Court to review the decision below. “Why it was taken” appears only when the majority opinion says lower courts disagreed or were unsure about the question; reasons that would fit any case (“to resolve the question presented”, “an important question”) are left out.
The law at issue
The law the Court was asked to apply, and the kind of power it used to decide.
- Provision
- 35 U.S.C. § 101
- Kind of law
- Infrequently litigated statutes
- Decided by
- Statutory construction
Data notes
The Supreme Court Database codes the main constitutional provision, statute or court rule each case turned on, and the basis of the decision: judicial review of a federal or state law, interpreting a statute, supervising the lower courts, and so on. A case can rest on more than one. “Overruled” counts only where the majority opinion says so.
Timeline
What happened at the Court and how the case got there, newest first.
- Jun 22, 1978DecidedDecided · Decided 6–3: reversed. Parker, Acting Commissioner of Patents and Trademarks won.
- Apr 25, 1978ArguedArgued · Oral argument before the Court.
- Not datedTaken upTaken up · The Supreme Court agreed to hear the case (certiorari).
- Not datedCourt belowCourt below · Began in and was decided by the U.S. Court of Customs and Patent Appeals: reversed.
Data notes
From the Supreme Court Database: the court the case began in, the court whose decision the Supreme Court reviewed and what that court did, how the case came to the Court, and the dates of argument and decision. The database does not date the steps in the lower courts. Court names are the database’s.
Other decisions on the same issue
10 other argued cases since 1946 on patents and copyrights: patentability of computer processes, newest first.
- Alice Corp. Pty. Ltd. v. CLS Bank Int'lLandmark · Copyright/Patents573 U.S. 208Jun 19, 2014 · 573 U.S. 208Economic activityLandmark · Copyright/Patents9–0Unanimous band
- Microsoft Corporation, Petitioner v. I4i Limited Partnership et al.564 U.S. 91Jun 9, 2011 · 564 U.S. 91Economic activity8–0Unanimous band
- Bernard L. Bilski and Rand A. Warsaw v. David J. Kappos, Under Secretary of Commerce for Intellectual Property and Director, Patent and Trademark Office561 U.S. 593Jun 28, 2010 · 561 U.S. 593Economic activity9–0Unanimous band
- Quanta Computer, Inc., et al. v. LG Electronics, Inc.553 U.S. 617Jun 9, 2008 · 553 U.S. 617Economic activity9–0Unanimous band
- Microsoft Corporation v. AT&T Corp.550 U.S. 437Apr 30, 2007 · 550 U.S. 437Economic activity7–18–1 band
- Ebay Inc., et al. v. Mercexchange, L. L. C.547 U.S. 388May 15, 2006 · 547 U.S. 388Economic activity9–0Unanimous band
- Diamond, Commissioner of Patents and Trademarks v. Bradley et al450 U.S. 381Mar 9, 1981 · 450 U.S. 381Economic activity4–45–4 band
- Diamond, Commissioner of Patents and Trademarks v. Diehr et al.450 U.S. 175Mar 3, 1981 · 450 U.S. 175Economic activity5–45–4 band
- Dann, Commissioner of Patents and Trademarks v. Johnston425 U.S. 219Mar 31, 1976 · 425 U.S. 219Economic activity7–0Unanimous band
- Gottschalk, Acting Commissioner of Patents v. Benson et al.409 U.S. 63Nov 20, 1972 · 409 U.S. 63Economic activity6–0Unanimous band
Data notes
Every other orally argued case with a clear vote, from the 1946 term on, that the Supreme Court Database files under the same issue as this one. The database gives each case one issue from a list of about 270 (abortion, search and seizure of vehicles, the death penalty, and so on), whatever law it turned on.
Official record
Read the full opinion on Justia, the argument audio on Oyez and Wikipedia. Case data from the Supreme Court Database, Version 2026 Release 01, through the 2025 term.