How to oppose a trademark application before IMPI and what to do if yours is opposed

Registering a trademark takes months, but the chance to stop someone else's application lasts only a short time. When someone applies to IMPI for a sign identical or similar to yours, the law opens a brief window to oppose it. If nobody notices in time, the application moves forward and, if it is registered, what remains is seeking invalidation.

Opposition also matters to applicants. If someone opposes your trademark, the Mexican Institute of Industrial Property (IMPI) will notify you and give you a deadline to respond. If you do not respond, your application is considered abandoned.

This article follows Mexico's Federal Law for the Protection of Industrial Property as amended by the reform published in the Federal Official Gazette on April 3, 2026. The reform has been in force since April 4, 2026. This article also follows the law's Regulations, published on April 28, 2026, which took effect sixty business days later, on July 23, 2026. Applications already pending on those dates are, in principle, concluded under the rules in force when they were filed.

What is an opposition to a trademark application?

It is the way for an interested party to tell IMPI why an application should not be granted. It is filed while the application is pending, before any registration exists.

After receiving an application, IMPI publishes it in the Industrial Property Gazette (Gaceta de la Propiedad Industrial) within ten business days. The publication includes the file number, the filing date, the sign applied for and the class.

Filing an opposition does not guarantee that the trademark will be refused. The law states that an opposition does not prejudge the outcome of IMPI's substantive examination. IMPI reviews on its own whether the trademark can be registered and, in the end, rules on the opposition with its own reasons and legal grounds.

How much time is there to file an opposition?

The deadline is one month and cannot be extended. It runs from the date on which the publication of the application in the Gazette takes effect. A late opposition is dismissed outright.

Acts published in the Gazette take effect on the date the Gazette itself indicates. If it indicates none, they take effect on the business day after the issue is released. Deadlines set in months run from date to date, including non-business days.

With up to ten business days to publish and one month to oppose, the window may close about six weeks after someone else files. That is why monitoring matters. The Gazette can be checked online from IMPI's official page, and reviewing it regularly helps you learn in time about applications similar to your trademark.

If you have not yet filed your own application, a prior search helps avoid the conflict from the start. We explain it in our article on registering a trademark in Mexico.

Who can oppose, and on what grounds?

Any person with an interest may file an opposition. It must rely on one of the grounds for refusal set out in the law. They include the following:

• An earlier trademark. The sign is identical or confusingly similar to a registered and current trademark or slogan, or to one applied for earlier, for the same or similar goods or services.
• A trade name used earlier. The sign is confusingly similar to the name of a company or establishment whose main line of business matches the goods or services in the application. That name must have been used before the filing date or the first-use date the applicant declared.
• A well-known or famous trademark. In the cases the law sets out, protection for these trademarks extends to any goods or services.
• Bad faith. The law describes it, among other cases, as applying for a sign to obtain an undue benefit to the detriment of its legitimate owner.
• Lack of distinctiveness. For example, signs that are generic, commonly used or descriptive of the goods or services they are meant to distinguish.

If your argument is that you were already using the trademark without registration, review the legal basis carefully. Prior use of a trademark does not appear as such among the grounds the law allows in an opposition. The law treats it as a ground to invalidate a registration already granted. In an opposition, that use may serve as evidence of another ground, such as bad faith or a trade name used earlier.

What must an opposition include?

The opposition is filed in writing with IMPI, together with the supporting evidence and proof of payment of the applicable fee. The Regulations allow filings to be made on paper or electronically.

All types of evidence are admitted except party admissions and witness testimony. They are admitted when the testimony or admission is contained in a document. Evidence contrary to public order or to the law is not admitted either.

It is worth gathering from the start whatever shows your right and the conflict. Depending on the case, the following may help:

• the registration certificate or the file number of your trademark;
• dated invoices, advertising, packaging or photographs showing use of your trademark or trade name;
• evidence that your trademark is well known, if you rely on that ground;
• documents showing a prior relationship with the applicant, if you allege bad faith;
• documents proving the authority of the person signing on behalf of a company.

If the opposition fails to meet a requirement, such as proof of authority or payment, IMPI issues a single request to the opponent. The opponent has five business days to cure it. If the opponent does not comply, or complies only in part, the opposition is dismissed outright.

There is another reason to prepare it well from the outset. Once IMPI has ruled on an opposition, it will not later admit an invalidation action based on the same arguments and the same evidence.

What happens after the opposition is filed?

When the opposition month ends, IMPI carries out the formal examination of the application and then the substantive examination. If it received an opposition, it notifies the applicant in writing. The applicant may then state its position and submit evidence.

Once the applicant's deadline has passed and the evidence has been processed, the file is made available to the applicant and the opponents. All of them may file closing arguments within five business days, and IMPI must take them into account. IMPI then issues its decision within a period that may not exceed five months.

The decision on the oppositions must state its reasons and legal grounds. For reference, when there are no office actions and no opposition, the law sets a maximum of five months from filing to decide the application. An opposition adds stages to that path. Both five-month periods mentioned in this section are new: the reform added them. Under the second transitory article of the decree, applications already pending on April 4, 2026 follow, in principle, the prior rules. The same article allows the mandatory-decision procedure created by the reform to be applied to those pending applications.

What should you do if someone opposes your application?

After the examination, IMPI will notify you of the opposition in writing. You have two months to respond and submit evidence. The law grants an additional two months, without a request, if you pay the fee that applies to the month in which you comply.

If you do not respond within the initial or the additional period, or you do not pay the fee, the application is deemed abandoned.

As a general rule, IMPI gives notice through the Gazette and sends an informational alert to the applicant. Notice is deemed given by publication alone, even if the alert does not arrive. For electronic filings, the rules of the agreement issued by IMPI also apply. Keep the address and email you gave in the application up to date, and check the file often.

When responding, identify which ground the opponent relies on and address that point with evidence. If the conflict involves an earlier trademark, the response may focus on the differences between the signs and between the goods or services of each.

Be careful about amending the application to avoid the conflict. If you change the trademark, add goods or services, or replace the ones you listed, the application becomes subject to a new filing procedure. Under the Regulations, changing the trademark's proportions, design, color or arrangement, or adding elements to it, counts as an amendment.

The new procedure is paid as a new application and is published again in the Gazette. Its filing date also becomes the date of the new procedure. Because that date sets priority between applications, yours may lose its place against others.

Can the parties settle it by agreement?

When the obstacle is an earlier trademark or a trade name, the law accepts the express written consent of its owner. With that document, the ground no longer applies to confusingly similar trademarks, or identical ones, for similar goods or services.

The Regulations require the consent to state the business origin of each sign and the goods or services it identifies. Depending on the case, it may also include limits on goods or services, the sectors or public each one targets and other rules to avoid confusion.

The applicant may file it with the application or when responding to an IMPI office action. Once given, the consent can only be invalidated by a court ruling. That is why it should be drafted with an eye to how both businesses will operate going forward.

What options remain once the deadline has passed?

If the other application is still pending but the month has expired, an opposition is no longer available. Even so, IMPI carries out its substantive examination to verify whether the trademark can be registered under the law.

If the trademark has already been registered, the route is to ask IMPI for an administrative declaration of invalidity (nulidad). The deadline depends on the ground. There are five years, counted from the date the publication of the registration in the Gazette takes effect, in these cases:

• the trademark is identical or confusingly similar to another used earlier and without interruption, in Mexico or abroad, for the same or similar goods or services;
• the registration was granted in error despite an earlier application or registration;
• the owner cannot prove the first-use date it declared.

In these other cases, invalidation may be sought at any time:

• the registration was granted in breach of the law;
• the registration was obtained in bad faith;
• an agent, representative, user, distributor or other party related to the owner of a trademark registered abroad obtained it without consent.

Invalidation is a separate procedure from opposition, with its own rules and evidence. If you already filed an opposition and IMPI ruled on it, remember that you cannot repeat the same arguments with the same evidence in an invalidation action.

Questions before opposing or answering an opposition

• On what date did the publication of the application in the Gazette take effect, and when does the month expire?
• Which legal ground supports the case: earlier trademark, trade name, well-known status, bad faith or another?
• Do I have dated evidence of use of my trademark or trade name?
• Who will sign the opposition, and what document will prove that person's authority?
• Am I filing my best arguments and evidence, knowing I cannot repeat them in an invalidation action?
• If I am the applicant, are the address and email in my file up to date?
• Does it make sense to seek a coexistence consent with the other party?

Start with the deadline questions. The month to oppose cannot be extended, and if the applicant does not respond, the application is abandoned. The rest tell you how strong the case is before you invest in it.

Official sources

The rules come from the current text of the Federal Law for the Protection of Industrial Property, as amended by the reform published in the Federal Official Gazette on April 3, 2026. The Gazette as the official means of publication and notice appears in Article 18. The informational alert appears in Articles 19 and 20, and the computation of deadlines in Article 21. The address and email for notices appear in Article 17. Publication of the application and the opposition deadline appear in Article 221. The form and evidence of an opposition appear in Article 222, and the request to the opponent in Article 223. The effect of an opposition on the examination appears in Article 224. The examination, notice to the applicant and the response deadlines correspond to Articles 225 and 226. Amendments that require a new procedure appear in Article 227, and priority by filing date in Article 220. Closing arguments and decision deadlines appear in Articles 229 and 229 Bis, and the mandatory-decision procedure in Article 327 Bis. The decision on oppositions appears in Article 230. The grounds that may be raised appear in Articles 12 and 173; those cited here are Sections I, I Bis, IV, XVI, XVII, XVIII, XIX and XXII of Article 173. Consent appears in the second-to-last paragraph of the same article. Invalidation and its deadlines appear in Article 258, and the bar on repeating arguments in Article 259. The reform's entry into force appears in the first transitory article of the amending decree, and application to pending matters in the second. From the Regulations to the Federal Law for the Protection of Industrial Property, Article 112 was used for the content of the publication and Article 113 for the request to the opponent. Amendments to the trademark appear in Article 117, and coexistence consent in Articles 88, 89, 90 and 91. Paper or electronic filing appears in Article 12. The Regulations' entry into force appears in their first transitory article, and application to pending matters in the third. July 23 results from counting sixty business days without May 1 and May 5. Both are non-business days under Article 28 of the Federal Law of Administrative Procedure and the IMPI agreement published on October 14, 2025. The Gazette can be checked from IMPI's official page.

This content is informational and does not constitute legal advice. Whether to file or answer an opposition depends on the signs, the goods or services, the available evidence and the dates in the file. It also depends on the rules that apply based on the date the trademark application was filed.