Supreme Court cases on patent eligibility under § 101
Section 101 of the Patent Act makes patentable "any new and useful process, machine, manufacture, or composition of matter." The Supreme Court has long read into it three implicit exceptions — laws of nature, natural phenomena, and abstract ideas — and its eligibility decisions define them. This page lists the principal Supreme Court § 101 decisions in chronological order with their holdings. The two-step test now applied by every court comes from Mayo (2012) and Alice (2014).
Foundations (1853–1948)
- O'Reilly v. Morse, 56 U.S. (15 How.) 62 (1853). Samuel Morse's eighth claim — to the use of electromagnetism, however developed, for marking characters at a distance — was invalid as too broad, because it claimed the principle itself rather than his particular means of applying it. Later § 101 cases cite Morse as the root of the concern about preemption.
- Funk Brothers Seed Co. v. Kalo Inoculant Co., 333 U.S. 127 (1948). A mixture of naturally occurring bacteria strains that did not inhibit one another was not patentable: the qualities of the bacteria were "the work of nature," and combining them produced no new property.
Algorithms and processes (1972–1981)
- Gottschalk v. Benson, 409 U.S. 63 (1972). A method for converting binary-coded decimal numbers into pure binary on a general-purpose computer was an unpatentable algorithm; the claim would wholly preempt the mathematical formula.
- Parker v. Flook, 437 U.S. 584 (1978). A method for updating alarm limits in catalytic conversion using a mathematical formula was ineligible; conventional post-solution activity could not transform an unpatentable principle into a patentable process.
- Diamond v. Chakrabarty, 447 U.S. 303 (1980). A genetically engineered bacterium capable of breaking down crude oil was a patentable "manufacture" or "composition of matter": the relevant line is between products of nature and human-made inventions. The Court quoted legislative history describing patentable subject matter as "anything under the sun that is made by man." (5–4.)
- Diamond v. Diehr, 450 U.S. 175 (1981). A process for curing synthetic rubber that used the Arrhenius equation to calculate when to open the mold was eligible: the claims, considered as a whole, applied the equation in an industrial process rather than claiming the equation itself. (5–4.)
The modern cases (2001–2014)
- J.E.M. Ag Supply, Inc. v. Pioneer Hi-Bred International, Inc., 534 U.S. 124 (2001). Newly developed plant breeds are eligible for utility patents under § 101, notwithstanding the separate Plant Patent Act and Plant Variety Protection Act.
- Bilski v. Kappos, 561 U.S. 593 (2010). A method of hedging risk in commodities trading was an unpatentable abstract idea. The machine-or-transformation test is "a useful and important clue" but not the sole test for process eligibility, and business methods are not categorically excluded.
- Mayo Collaborative Services v. Prometheus Laboratories, Inc., 566 U.S. 66 (2012). Claims to adjusting a thiopurine drug dose based on measured metabolite levels effectively claimed a law of nature; the additional steps were well-understood, routine, conventional activity. Mayo framed the inquiry that became step two of the modern test: whether the claim adds an "inventive concept" sufficient to ensure it amounts to significantly more than the natural law itself. (Unanimous.)
- Association for Molecular Pathology v. Myriad Genetics, Inc., 569 U.S. 576 (2013). A naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated, but synthetically created complementary DNA (cDNA) is eligible because it is not naturally occurring. (Unanimous in relevant part.)
- Alice Corp. v. CLS Bank International, 573 U.S. 208 (2014). Claims to a computerized scheme for mitigating settlement risk through a third-party intermediary were ineligible. The Court applied Mayo's framework to abstract ideas, producing the two-step test: (1) are the claims directed to a patent-ineligible concept; and (2) if so, do the elements, individually and as an ordered combination, add an inventive concept that transforms the claim into a patent-eligible application? Implementing an abstract idea on a generic computer does not suffice. (Unanimous.)
Since Alice
The Supreme Court has not decided a § 101 case on the merits since Alice. It has denied a series of petitions asking it to clarify the test, including in American Axle & Manufacturing, Inc. v. Neapco Holdings LLC, where certiorari was denied in 2022 even though the Solicitor General had recommended review.
The working law of eligibility has therefore been developed by the Federal Circuit, in decisions such as Enfish, LLC v. Microsoft Corp., 822 F.3d 1327 (Fed. Cir. 2016) (specific improvements to computer functionality are not abstract), McRO, Inc. v. Bandai Namco Games America Inc., 837 F.3d 1299 (Fed. Cir. 2016), BASCOM Global Internet Services, Inc. v. AT&T Mobility LLC, 827 F.3d 1341 (Fed. Cir. 2016), and Berkheimer v. HP Inc., 881 F.3d 1360 (Fed. Cir. 2018) (whether claim elements are well-understood, routine, and conventional can raise a question of fact). See subject matter eligibility under § 101 for the doctrinal framework.
Bills to rewrite § 101, including versions of the Patent Eligibility Restoration Act, have been introduced in Congress in several sessions. As of this page's last review, none has been enacted. The USPTO separately publishes examination guidance on eligibility, which binds examiners but not courts.
How to use these cases
- For software and business-method claims, start with Alice and Bilski, then the Federal Circuit's step-one cases (Enfish, McRO) and step-two cases (BASCOM, Berkheimer).
- For diagnostics and natural laws, start with Mayo and Myriad; for engineered organisms and compositions, Chakrabarty.
- Diehr remains the leading example of an eligible process that uses a mathematical formula, and is frequently contrasted with Benson and Flook.
- Eligibility may be raised on a motion to dismiss, on summary judgment, or at trial, and may be raised at the PTAB in post-grant review but not in inter partes review.
Frequently asked questions
Which Supreme Court case created the two-step test for § 101?
The framework originated in Mayo v. Prometheus (2012) and was formalized and extended to abstract ideas in Alice Corp. v. CLS Bank (2014). Courts call it the Alice/Mayo test.
What are the judicial exceptions to § 101?
Laws of nature, natural phenomena, and abstract ideas. Claims directed to one of them are ineligible unless they add an inventive concept amounting to significantly more than the exception itself.
Has the Supreme Court decided a § 101 case since Alice?
No merits decision as of this page's last review. The Court has denied several petitions, including American Axle v. Neapco in 2022, leaving development of the test to the Federal Circuit.
Can software be patented after Alice?
Yes, if the claims are not directed to an abstract idea — for example, a specific improvement in computer functionality, as in Enfish (2016) — or if they add an inventive concept beyond generic computer implementation.
See also
- Subject matter eligibility under § 101The Alice/Mayo framework as applied today.
- Alice Corp. v. CLS BankFacts, holding, and reasoning of the 2014 decision.
- Post-grant reviewThe PTAB proceeding in which § 101 can be raised.
- Title 35 referenceSection 101 in the context of the Patent Act.
Last reviewed: October 2026