§101 case law

The cases that decide what's patentable.

Patent eligibility under 35 U.S.C. §101 is shaped less by the statute than by a handful of decisions. Here is each landmark case — what the court held, which side of the line it drew, and why it still matters when you draft a claim today.

1. 1972

   Gottschalk v. Benson

   IneligibleAbstract ideaSupreme Court

   An algorithm for converting binary-coded-decimal numbers into pure binary was held to be an unpatentable abstract idea — patenting it would have pre-empted the mathematical formula itself.

   WhyThe original 'you can't patent math' decision. It still anchors why pure algorithms and formulas, claimed in the abstract, are ineligible.

2. 1978

   Parker v. Flook

   IneligibleAbstract ideaSupreme Court

   A new formula for calculating alarm limits, paired only with conventional post-solution activity, remained ineligible — a novel formula does not become patentable just by adding a routine final step.

   WhyForeshadowed the 'significantly more' requirement: tacking conventional steps onto an exception is not enough to make it eligible.

3. 1980

   Diamond v. Chakrabarty

   EligibleNatural phenomenonSupreme Court

   A genetically engineered, oil-eating bacterium was patentable subject matter. The famous line — patentable subject matter includes 'anything under the sun that is made by man' — turned on the organism having markedly different characteristics from anything in nature.

   WhyThe cornerstone of biotech patenting: human-made living things with new characteristics are eligible, unlike the naturally-occurring organism.

4. 1981

   Diamond v. Diehr

   EligibleAbstract ideaSupreme Court

   A rubber-curing process that used the Arrhenius equation to decide when to open the press was eligible. A process is not unpatentable simply because it contains a mathematical formula, so long as it applies that formula in a specific, useful way.

   WhyThe classic 'practical application' win. It is the model for drafting software and process claims that survive §101 by improving a concrete technical process.

5. 2010

   Bilski v. Kappos

   IneligibleAbstract ideaSupreme Court

   A method of hedging risk in commodities trading was an abstract idea — a fundamental economic practice. The Court also held that the machine-or-transformation test is a useful clue, but not the sole test, of eligibility.

   WhyEstablished that business methods and fundamental economic practices are abstract ideas, setting up the analysis Alice would formalize.

6. 2012

   Mayo v. Prometheus

   IneligibleLaw of natureSupreme Court

   A claim relating drug-metabolite levels to dosage adjustments recited a law of nature, and the extra steps were well-understood, routine, and conventional — not enough to make it eligible.

   WhyCreated the two-step inquiry (later carried into Alice) and remains the reason diagnostic-method claims are so hard to patent.

7. 2013

   AMP v. Myriad

   Split resultNatural phenomenonSupreme Court

   Isolated, naturally-occurring DNA is a product of nature and ineligible, even though isolating it took effort — but synthetic complementary DNA (cDNA) is eligible because it is not naturally occurring.

   WhyDraws the line for genetic and natural-product patents: claim what you made (cDNA, engineered sequences), not what nature already made.

8. 2014

   Alice Corp. v. CLS Bank

   IneligibleAbstract ideaSupreme Court

   Computer-implemented intermediated settlement was an abstract idea, and running it on a generic computer added nothing inventive. The Court applied the Mayo two-step framework to all judicial exceptions.

   WhyThe single most cited eligibility case. 'Do it on a computer' is the canonical example of a claim that fails — every software filer must clear Alice.

9. 2016

   Enfish v. Microsoft

   EligibleAbstract ideaFederal Circuit

   A self-referential database table was directed to a specific improvement in how computers store and retrieve data, so the claim was not directed to an abstract idea at step one of the test.

   WhyThe leading software win: claims aimed at a concrete improvement in computer functionality can pass at step 2A without ever reaching the inventive-concept question.

10. 2016

    BASCOM v. AT&T

    EligibleAbstract ideaFederal Circuit

    Even though content filtering was an abstract idea, the specific, non-conventional arrangement of otherwise-known elements supplied an inventive concept at step two — making the claim eligible.

    WhyShows the step-2B escape hatch: an unconventional ordered combination of known pieces can be 'significantly more,' even when each piece is generic.

This is plain-English education, not legal advice. Eligibility is fact-specific and the case law keeps evolving — for a real opinion on your invention, work with a registered patent attorney. PatentBrief is not a law firm.

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