Patentable Subject Matter (35 USC 101; MPEP 2100)

by patentbar on November 21, 2007 · 32 comments

in 35 USC 101, MPEP 2100

MPEP Chapter 2100 covers the fundamental issues of patentability – what is patentable subject matter and how that matter must be expressed in an applicant’s disclosure. The Prometric Patent Bar tests MPEP 2100 heavily.

Note: MPEP 2100 also includes 35 USC 102 (a)-(g), 35 USC 103 and 35 USC 112, which are discussed in other posts under MyPatentBar’s Study Guide, PART 2.

What is patentable subject matter? Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefore, subject to the conditions and requirements of this title.” [35 USC 101]

To be patentable an invention must fall into one of the following statutory categories:
1) machine – e.g., new gizmo
2) manufacture (combination of materials) – e.g., new widget (gardening tool, computer chip)
3) composition of matter – e.g., new chemical composition or metal alloy
4) process (a new method for doing something) – note: special sub-category product by process

A claim cannot cite more than one of the statutory categories above (i.e., it is inappropriate to refer to a machine and composition of matter in the same claim).


  • Product: a new, useful and non-obvious machine, manufacture, or composition of matter (see statutory categories 1-3 above).
  • Process: a new, useful and non-obvious way of doing something, making something, or using something. A process may be patentable even though the resulting product itself is not.  Also, a process claim must include steps; it cannot claim the result without any steps (see comment below).
  • Product-by Process: patentability is based on the product, not the process. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious over a product in the prior art, the claim is unpatentable even though the prior product was made by a different process.
    • Living subject matter is patentable: human intervention is necessary (e.g., genetically engineered material)
    • Also patentable are claims directed to a practical application of a natural phenomenon

    Not Patentable – examples

    • Naturally occurring living subject matter or raw materials
    • Inventions for which the broadest reasonable interpretation encompasses a human being
    • Mathematical, physical and natural laws
    • Processes that depend on natural laws, abstract ideas, etc. without some claimed practical application
    • Computer-related, descriptive material; this is copyrightable

    How that matter must be expressed in an applicant’s disclosure; Claim Interpretation

    • During examination, claims must be “given their broadest reasonable interpretation consistent with the specification.”
    • The words of the claim must be given their “plain meaning” unless they are defined in the specification.
    • The transitional phrases “comprising,” consisting essentially of,” and “consisting of” define the scope of a claim with respect to what unrecited additional components if steps, if any, are excluded from the scope of the claim. [MPEP 2111.03]
      • Comprising – non-exclusive language
      • Consisting essentially of – limiting language*
      • Consisting of – exclusive language*

      *revised from dk’s comment below

    1 patentbarNo Gravatar November 28, 2007 at 12:41 am

    examiner has burden to prove unpatentability by preponderance of evidence (51%)

    2 dkNo Gravatar February 13, 2008 at 9:25 pm

    I first want to thank you for setting this website. It is a invaluable tool for me to prepare for the patent bar.

    I think your last bullets about transitional phrases have a misinformation. I think it should be

    * Comprising – non-exclusive language
    * Consisting essentially of – limiting language
    * Consisting of – exclusive language

    because MPEP 2111.03 states that:
    “A ‘consisting essentially of’ claim occu­pies a middle ground between closed claims that are written in a ‘consisting of’ format and fully open claims that are drafted in a ‘comprising’ format.”

    3 patentbarNo Gravatar February 21, 2008 at 11:48 pm

    A product-by process is a claim that encompasses the product produced by claim #1. It is the product and not the process that determines patentability. You already have a claim directed toward the process (claim #1). For example, in the same application – you have claim #1 (the process) and claim #2 (the product-by process).

    4 patentbarNo Gravatar February 22, 2008 at 12:01 am

    A proper process claim must include the actual steps. (For example, a process of “doing something” comprising of … and lists a series of steps). “The use of a water replant paint to water-proof patio furniture” – does not recite specific acts for how that process is accomplished, and is not a proper process claim. YOU MUST CITE the steps involved to achieve a result, just citing the result is not sufficient.

    5 patentbarNo Gravatar February 22, 2008 at 12:11 am

    To satisfy the utility requirement (part 2 of USC 101), you must only state a benefit. When there is a lack of utility, you will usually also have a lack of enablement (USC 112 p1). This means that a rejection based on utility will accompany a rejection based on enablement.

    6 JBagNo Gravatar September 18, 2009 at 5:27 pm

    One way I remember the differences between consisting and comprising is that “consisting is consistant where comprising can compromise.”

    7 DanTNo Gravatar August 4, 2011 at 12:56 pm

    Does anyone have experience using the OmniPrep patent bar prep course?

    I am a recent law school graduate looking to start preparing for the patent bar, and I was curious if anyone had any recommendations related to professional preparation courses.

    OmniPrep is by far the most reasonably priced I have found, but if I am going to invest the time I want to make certain I am putting myself in a position to pass.

    Any insight would be greatly appreciated.

    8 BobNo Gravatar August 4, 2011 at 6:21 pm

    I don’t know much about OmniPrep, but I’ve heard it’s not the best. You can find a used PLI course on eBay for the same or even less. That’s what I used to pass and it was great.

    9 BobNo Gravatar August 4, 2011 at 6:31 pm

    I still have mine for sale if you are interested.

    10 DavidNo Gravatar August 4, 2011 at 9:42 pm

    I agree with Bob, PLI is the best way to go. I don’t know much about Omni but PLI was great in explaining the materials and it helped me pass.

    11 SundayNo Gravatar August 29, 2011 at 11:40 am

    David. Can you please send me a detailed information on the PLI materials. I will like to buy them for my preparation for the patent bar examintion.

    12 DanTNo Gravatar August 5, 2011 at 3:35 pm


    What year is your course from? Does it include the new material on the exam?

    Send me an email at when you get a chance, I would be interested in buying your materials.

    13 TonyNo Gravatar May 9, 2012 at 11:46 pm

    Anyone have a 2012 PLI course that I can buy?

    14 doraNo Gravatar May 17, 2012 at 11:11 pm

    Any PLI materials for sell?

    15 RMNo Gravatar September 9, 2013 at 6:47 pm

    Any PLI material including AIA for sale? Email me at

    16 BBNo Gravatar October 29, 2013 at 11:19 am

    Same as RM. Please email if you want to sell your PLI material with AIA.

    17 Patent 14No Gravatar December 16, 2013 at 1:06 am

    I am looking for PLI material with AIA. Please email me at

    18 patentNo Gravatar March 29, 2014 at 10:35 am

    I am going to start preparing for patent bar exam and I am interested to buy PLI current material with AIA. Thank you.

    19 DaniyalNo Gravatar April 8, 2014 at 6:46 pm

    I am going to prepare for patent bar exam, please email me if someone have the latest PLI material with AIA. Thank you.

    20 kansas manNo Gravatar May 10, 2014 at 2:19 pm

    i do email me at kansasman2014 at yahoo

    21 DaniyalNo Gravatar April 8, 2014 at 6:47 pm
    22 PaulinaNo Gravatar May 9, 2014 at 2:59 pm

    I am also looking to but the latest PLI material. I am hoping to take the patent bar before the end of the summer. Thank you!

    23 himaNo Gravatar June 11, 2014 at 2:04 pm

    I am interested in taking the patent Bar exam by beginning of this fall. I am looking for study material. I was thinking to buy OMNI prep. Please recommend a good study material for me. I am thinking between OMNI and PLI study guides. Please suggest me which one would be good. If anybody has PLI study material I am willing to buy.Thank you in advance!

    24 Bfusion.No Gravatar June 11, 2014 at 5:53 pm

    Hi Hima,

    If you haven’t taken a look, Wysebridge Patent Bar Review is another option for you. When I was going through my studies before passing the exam, I was on these forums a lot, getting feedback and sharing a lot of my own study resources I had compiled. Those beginnings, tutoring others, providing focused study materials led to the development of what would become Wysebridge Patent Bar Review. The program was built rom the ground up, to be focused for today’s exam, 100% online (and smartphone + tablet functional as well), including the AIA changes.

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    25 Afroso AgyemanNo Gravatar September 28, 2015 at 2:02 am

    A process (a new way of doing something) is patentable. Therefore, in a Product-by Process: wherein patentability is based on the product, and not the process. can the applicant resort to claiming the “Process”. If the product in the product-by-process claim is the same as or obvious over a product in the prior art. But the process of producing the rejected product is new, useful and non-obvious? Because the prior product can now be produced via the useful and novel process? Also, can the product-by-process category contravene the requirement that a claim cannot cite more than one statutory category from the point of view that both product and process can be new, useful and non-obvious at the same time?

    26 TechguyNo Gravatar November 24, 2015 at 4:45 pm

    I am a Software Engineer with a lot of experience, no law background. How hard is it for me to self study and pass the Patent Bar. Thinking of working as a Patent Agent

    27 RushikeshNo Gravatar December 14, 2015 at 7:35 am

    hey guys, I need some advice on studying programs

    28 mayteaNo Gravatar January 18, 2016 at 10:12 am

    My feedback is using omni prep has been a struggle. Lots of typos and information that is unclear outdated. Feedback to questions has been nearly zero. Most of the info can be found at other sources. They do have some newer material on AIA just added.

    I will give a plug to the Penn University 27 part IP class on Youtube. I would highly recommend to do this at very beginning. It is notice to see these put out for others outside the law program to review.

    29 NewlyMintedNo Gravatar December 16, 2015 at 6:18 pm

    I just passed the Patent bar exam last night on my first try and I wanted to thank the folks on this website for sharing their experiences and general information about the exam. I used the PLI home study course and went to the Live session (1 week). I thought it was very useful. I wish everyone studying for the exam all the best. Also, try not to panic during the exam. I thought I was going to fail throughout the exam and tried shaking the negative thoughts. After the survey, I received a preliminary result that I passed. Good Luck folks!!!

    30 PutInTheTimeNo Gravatar December 18, 2015 at 1:04 am

    I just passed the exam- and wanted to thank all those who contributed to this site- I used PLI too and passed on my first try- no patent law experience. It took me about a month of intense full time studying- lots of repeats from the October and April 2003 exams- lipgloss, PCT fax exceptions, appeal reply briefs, who can sign the terminal disclaimer, foreign priority, all sorts of obviousness and how to overcome obviousness rejections- maybe 5 AiA questions at most. But honestly, review the April and October 2003 exams- understanding each and every question, why the right answers are right and wrong ones are wrong and lookup the answers in the MPEP. Same thing for every question on this site and you will pass! Good Luck!

    31 KMcCNo Gravatar February 3, 2016 at 1:01 pm

    Hey @PutInTheTime would you like to sell you PLI materials? I am looking to buy some used, but can only find pre-AIA stuff. Let me know!

    That goes for everyone!

    Thanks :)

    32 MichelleNo Gravatar June 13, 2016 at 3:32 pm

    Please email me if anyone has the latest PLI materials with AIA for sale. Thank you.

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