How Do I Stop or Sue a Trademark Infringer?

Prevent trademark infringement of your business name or product name.

By , Attorney · University of San Francisco School of Law
Updated by Brian Farkas, Attorney · Benjamin N. Cardozo School of Law

Trademark law allows you to protect names, logos, and other commercial signifiers used to identify products and services. Although there is no requirement that you must register your mark federally with the U.S. Patent and Trademark Office, doing so has multiple advantages, including providing notice to the public of your ownership of the mark, a presumption of ownership nationwide, and the exclusive right to use the mark in connection with the goods and/or services listed in the registration.

As the owner of a trademark, you can stop others from using your mark, or a confusingly similar one. If you discover that another person or company is infringing on your mark, what can you do?

Send a Cease-and-Desist Letter

When you find that your mark is being used by an unauthorized person or company, filing a lawsuit is typically not the most sensible first step. Not only is a lawsuit expensive, but it is also a lengthy legal proceeding that will take significant amounts of both time and money. For most business owners, lawsuits are rarely the optimal first move.

A more efficient first step is to send what intellectual property attorneys call a cease-and-desist letter. This is essentially a demand letter, addressed to the trademark infringer, succinctly and clearly explaining the infringement.

It is possible that the infringer simply did not know about your pre-existing trademark. It is also possible that the infringer did know about your trademark, and was trying to ride off your goodwill with your consumers. Whatever the case, your letter would indicate that the infringer must stop using your mark within a certain short period of time, typically five business days.

If your letter is ignored, you can use it as evidence in a lawsuit that you at least tried to negotiate with the infringer in good faith before jumping into litigation.

You may wish to hire a lawyer to write a cease-and-desist letter, as letters on law firm letterhead will often be taken more seriously by infringers. But you are also permitted to send such a letter yourself, ideally on your company's letterhead. See Nolo's Guide to Drafting Cease-and-Desist Letters.

Filing a Trademark Infringement Lawsuit

If your cease-and-desist letter is ignored, then you may decide that you have little choice but to sue. There are several potential claims and considerations that you might make in your trademark infringement lawsuit.

Likelihood of Confusion

First, trademark law is designed to protect consumers. Even though trademarks certainly benefit businesses, courts are sensitive to the need for consumers to correctly and quickly identify the origin of the goods and services that they purchase. Thus, under the trademark statute, courts will consider whether there is a "likelihood of confusion" between your mark and the infringing mark. In other words, would the average consumer in the relevant market be confused as to the origin or source of the product?

When considering whether a trademark is being infringed by a confusingly similar mark, a court will consider a variety of factors. These include:

  • whether the trademark is being used on competing goods or services (goods or services compete if the sale of one is likely to affect the sale of the other)
  • whether consumers would likely be confused by the dual use of the trademark, and
  • whether the trademark is being used in the same part of the country or is being used on related goods (goods that will likely be noticed by the same customers, even if they don't compete with each other).
Note that no single factor is determinative. These are merely issues that will weigh on a court's mind in evaluating the likelihood that a consumer will be confused.

Trademark Dilution and Tarnishment

In addition to claiming that there is a likelihood of confusion with an infringing mark, you can also claim that the infringing mark is "tarnishing" or "diluting" yours. Under federal (and some state) laws known as dilution statutes, you may go to court to prevent your trademark from being used by someone else if your mark is famous and the other company's use would negatively impact the mark's strength.

Put differently, dilution of your mark occurs when another user's use of the mark weakens its reputation for quality (called "tarnishment") or renders it common through overuse in different contexts (called weakening). The key element is that your mark is famous, distinctive, and recognizable.

Dilution statutes apply even if there is no way customers would be likely to confuse the source of the goods or services with those sold by the owner of the famous mark. For instance, consumers might not think that Microsoft toilet paper is associated with Microsoft, the software company, but makers of Microsoft toilet paper could still be forced to choose another name under federal dilution law.

Using a Trademark Actively

Before running to court, remember that you must be actually using your trademark in order to prevent others from using it. A business that claims to own a trademark cannot stop others from using the same or a similar trademark unless it is actively using the trademark itself.

In trademark law, "using" a trademark means putting it to work in the marketplace to identify goods or services. This does not necessarily mean that the product or service actually has to be sold, as long as it is legitimately offered to the public under the trademark in question. Remember, trademarks are designed to help the marketplace and consumers more than the "owner" of the trademark. An unused trademark will receive minimal protection from the courts.

For example, let's say Robert creates a website where he offers his new invention, a humane mousetrap, for sale under the trademark "MiceFree." Even if Robert does not sell any traps, he is still "using" the trademark as long as "MiceFree" appears on the traps or on tags attached to them and the traps are ready to be shipped when a sale is made.

Similarly, if Kristin, a probate attorney, puts up a website to offer her services under the mark "Probate Queen," her service mark will be in use as long as she is ready to respond to customer requests for her advice.

Talk to a Lawyer

Need a lawyer? Start here.

How it Works

  1. Briefly tell us about your case
  2. Provide your contact information
  3. Choose attorneys to contact you
Get Professional Help

Talk to a Intellectual Property attorney.

How It Works

  1. Briefly tell us about your case
  2. Provide your contact information
  3. Choose attorneys to contact you