What’s a “Double Patenting” Rejection?

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lighthouse in Newport, OregonOur clients often file continuation applications, whether it’s to broaden the scope of coverage, to shift the scope, or just to maintain an active application for deterrence purposes. Continuations are a great strategy for building your patent portfolio.

When you file multiple patent applications over time, however, you may eventually run into a rejection from the USPTO based on something called “Double Patenting.” What does that mean? Is it serious?

In a typical scenario, you’re pursuing a continuation application with a new set of patent claims. By definition, that means there’s a “parent” patent with its own set of claims. There are two main types of double patenting rejections.

A. Statutory Double Patenting

The patent statutes say you can have “a patent” on an invention. In other words: one patent, not two.

This isn’t what it sounds like. You’re allowed to have more than one patent related to the same invention. Just not worded exactly the same way.

In the context of patent law, every patent claim is technically a different invention. Since you can’t have more than one patent on an invention, that means you’re not permitted to have two claims that are identical.

Sometimes, a claim in a continuation will be very close to (or maybe even the same as) one in the parent patent.

Responding to a Statutory Double Patenting Rejection

In general, if the claims are actually identical, you’ll need to either cancel or modify them.

However, the Examiner could also be wrong. Even if there’s just one word difference, that could be enough. The general test is this: can you think of a way to infringe one of the claims but not the other? If so, they’re not actually identical.

B. Non-statutory Double Patenting

Over the years, courts have decided that certain rules must apply to claims of a continuation that are “obvious” when compared to claims of the parent application. So, even if the claims aren’t identical, they can often be close enough that the Examiner will issue a “non-statutory” rejection.

Responding to a Non-Statutory Double Patenting Rejection

Compared with the statutory version, there are more options to consider with this type of rejection. Here are a few to discuss with your patent attorney:

Option 1: Defer

You might be able to defer your response on this one. If you’re planning to change the claims for some other reason, the double patenting situation may go away. It can be a good idea to save yourself the consequences of a terminal disclaimer. Maybe wait and see, if that’s a possibility.

Option 2: Terminal Disclaimer

In general, there are two reasons why the non-statutory double patenting rejection exists.

1. The Patent Office does not allow an applicant to obtain a length-of-term benefit from having claims on the same subject matter in two different patents. Accordingly, the applicant is required to forego (i.e., “disclaim”) any potential period of time where the new patent would outlast the earlier one (AKA the “terminal” period).

2. The Patent Office also does not allow two different entities to be able to enforce the same patent rights. Accordingly, both of the patents are required to remain under the same ownership.

Based on that, applicants usually file a standard form known as a Terminal Disclaimer. The actual language of the terminal disclaimer is below, but it says that (a) the second patent won’t be allowed to extend its coverage for a longer time than the first one, and (b) the new patent won’t be enforceable if it’s not under the same ownership as the first one.Your law firm will normally file the form on your behalf.

The relevant language of the USPTO Terminal Disclaimer form is reproduced below.

  • The applicant . . . hereby disclaims, except as provided below, the terminal part of the statutory term of any patent granted on the instant application which would extend beyond the expiration date of the full statutory term of prior patent No. ___, as the term of said prior patent is presently shortened by any terminal disclaimer. The applicant hereby agrees that any patent so granted on the instant application shall be enforceable only for and during such period that it and the prior patent are commonly owned. This agreement runs with any patent granted on the instant application and is binding upon the grantee, its successors or assigns.
  • In making the above disclaimer, the applicant does not disclaim the terminal part of the term of any patent granted on the instant application that would extend to the expiration date of the full statutory term of the prior patent, “as the term of said prior patent is presently shortened by any terminal disclaimer,” in the event that said prior patent later: expires for failure to pay a maintenance fee; is held unenforceable; is found invalid by a court of competent jurisdiction; is statutorily disclaimed in whole or terminally disclaimed under 37 CFR 1.321; has all claims canceled by a reexamination certificate; is reissued; or is in any manner terminated prior to the expiration of its full statutory term as presently shortened by any terminal disclaimer.

Option 3: Amendment of the Claim(s)

If you can’t defer and don’t wish to proceed with the Terminal Disclaimer, there is another route available. Namely, you can amend the claims in question to include additional limitations that wouldn’t be considered obvious. However, this may be less desirable, because it narrows your scope of protection.


A double patenting rejection usually isn’t too serious of a problem, in the grand scheme of things. However, as you can see above, there is much to consider if you find yourself in this situation. As always, if you have any questions, or if we can help you out in any way, please don’t hesitate to call or email.


Be sure to visit our Ultimate Guide to Patents for Your Business

Photo © 2013 Monica Bourgeau

Blog Post © 2019 Kolitch Romano LLP

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DISCLAIMER: This article is intended to give the reader an overview of the topic, and does not constitute legal advice as to any particular fact situation. Facts matter, and every situation is different. In addition, laws and their interpretations change over time and the contents of this article may not reflect these changes. You are strongly advised to consult competent legal counsel regarding your particular situation.