I got a cease and desist letter – what should I do?


Patent owners, corporations and private individuals alike, are usually prepared to react to potential patent infringements. Whether the infringement was real or not, the owner’s first reaction normally is to send a cease and desist letter to the accused infringer.

The letter notifies the recipient of the possible infringement and states the patent owner’s demands to rectify the situation. It may also include a warning about further legal action in case the adverse party doesn’t comply with the patent owner’s demands.

To keep the story short, this blog post is about patents, but the advice I’m going to give apply to utility models as well, and for the most part also to trademarks and design rights.

Clarify the situation by checking the facts

Receiving a cease and desist letter can feel stressful, intimidating, and even unfair, especially if you created your product entirely on your own and had no reason to assume that someone else could own exclusive rights to it. If you’re confused, you can make the situation clearer by checking some basic facts. After that, you’ll be able to better evaluate the consequences and their likelihood.

If the sender of the letter proposes discussions for reasonable license fees, constructive negotiations could be the best way to handle the situation. Being up to date with the facts gives you a much stronger position in the negotiations.

Are all the necessary details included?

First, check that the letter includes all details you need to know in order to take any action at all. It is the patent owner’s duty to specify what has caused the infringement and identify the patent that is allegedly being infringed. I can tell you it’s not uncommon that a cease and desist letter could completely fail to identify, for example, the product that the patent owner finds infringing.

Some large, international corporations are a class of their own – they might send the same generalized letter to numerous other businesses in their field. Recipients would be demanded to join a licensing program covering the sender’s massive patent portfolio, without being given any real reasons for such demands.

If the recipients of the letter have been selected randomly, you can take it as seriously as any other mass-mailed money-collecting letter sent purely for profit-gaining purposes.

If the letter actually manages to identify the patent, you could now consult the public patent registers to check:

– if the patent has been granted, and if so, in what form,
– if the patent is valid in a relevant country, and
– whether it is registered at all to the sender of the letter.

The exclusive right given by a patent may only be exercised by the right holder recorded in a public register, or by a party authorized by agreement with the right holder. Sometimes, for instance in case of a merger, all changes in ownership brought about by the merger may not necessarily have been registered; in this situation, a company believing to own the patent would not actually be the publicly registered patent holder, and as a result not entitled to send the cease and desist letter.

Is the patent coverage as broad as alleged?

One essential check is to evaluate the scope of protection of the independent claims. This is important because often the scope of protection, or coverage of the patent, needs to be narrowed down to some extent during the examination process, as compared to the originally filed application. The patent owner, however, may still have the impression of the broader scope of the original application, and in that case may end up sending cease and desist letters also to recipients whose products don’t in reality infringe the patent in its final, granted form.

To evaluate the scope of protection of the patent, you can look up the file history that documents the correspondence between the patent owner and the patent office recorded in the public registers during examination.

And finally, even if all the checks you’ve made up to this point suggested that the patent owner could have legitimate reasons to impose demands on you, remember that the examination carried out by the patent office is by no means complete.

Anyone can request a granted patent to be fully or partly revoked, if they can prove that at least one of the features falling within the scope of protection of an independent claim was known to the public before the filing date of the patent application.


Often the first checks already help you to clarify the situation, and you’ll be able to better analyze the risks posed by the cease and desist letter. An experienced patent attorney can be an invaluable help if you’ve received a cease and desist letter and have no idea what to do. Here at Papula-Nevinpat, our experts in IP protection will advise you in all infringement and opposition issues.


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