Diamond, Commissioner of Patents and Trademarks v. Diehr et al.
The Court held that controlling the execution of a physical process, by running a computer program did not preclude patentability of the invention as a whole.
450 U.S. 175 · No. 79-1112 · 1980 term · Burger Court
Decided Mar 3, 1981 · argued Oct 14, 1980
Economic activity · Patents and copyrights: patentability of computer processes
Majority opinion: William Rehnquist
The voteMajorityDissent
5–45 in the majority, 4 in dissent
4 dissents (5–4)
Affirmed. Diamond, Commissioner of Patents and Trademarks lost.
What this ruling means
Affirmed: the Supreme Court upheld the decision of the U.S. Court of Customs and Patent Appeals, so it stands (sometimes with changes the Court made to it).
Diamond, Commissioner of Patents and Trademarks was the petitioner, the side that asked the Supreme Court to review the case. “Lost” means the Court did not give 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.
Diamond v. Diehr, 450 U.S. 175 (1981), was a United States Supreme Court decision which held that controlling the execution of a physical process, by running a computer program did not preclude patentability of the invention as a whole. The high court reiterated its earlier holdings that mathematical formulas in the abstract could not be patented, but it held that the mere presence of a software element did not make an otherwise patent-eligible machine or process patent ineligible. Diehr was the third member of a trilogy of Supreme Court decisions on the patent-eligibility of computer software related inventions.
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 1980 term. Filled: the 5 in the majority. Hollow: the 4 in dissent. Colour is the party of the president who appointed them.
Majority(5)
William RehnquistWrote the majority opinion
Byron WhiteJoined the majority
Potter StewartJoined the majority
Lewis PowellJoined the majority
Warren BurgerJoined the majority
Dissent(4)
John StevensWrote a dissent
Thurgood MarshallJoined a dissent
William BrennanJoined a dissent
Harry BlackmunJoined 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
- Diamond, Commissioner of Patents and TrademarksPatent Office, or Commissioner of, or Board of Appeals
- Respondent
- Diehr et al.Inventor, patent assigner, trademark owner or holder
- Reached the Court by
- Certiorari (the Court chose to hear it)
- Why it was taken
- Federal appeals courts had ruled differently, and the question was important
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.
- Mar 3, 1981DecidedDecided · Decided 5–4: affirmed. Diamond, Commissioner of Patents and Trademarks lost.
- Oct 14, 1980ArguedArgued · Oral argument before the Court.
- Not datedTaken upTaken up · The Supreme Court agreed to hear the case (certiorari). Federal appeals courts had ruled differently, and the question was important.
- 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
- Parker, Acting Commissioner of Patents and Trademarks v. Flook437 U.S. 584Jun 22, 1978 · 437 U.S. 584Economic activity6–36–3 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.