Defending a Registered Trademark: Infringement, Enforcement, and Staying Protected

A registration gives you the legal right to stop others from using a conflicting mark. It doesn't stop them for you. Defending a mark after registration is separate, ongoing work — distinct from monitoring, which is how you find out something's wrong. This guide covers what you actually do once you have: recognizing real infringement, sending a cease-and-desist letter, opposing a new conflicting application, and the maintenance obligation most owners never hear about until it's relevant — staying vulnerable to cancellation if the mark sits unused for too long.

Recognizing potential infringement

Not everything that looks similar to your mark is infringing it, and treating every similar name as a threat wastes time and credibility. What actually matters is the same core analysis an examiner applies to a new application under relative grounds: is the other mark identical or deceptively similar to yours, is it being used on the same or closely related goods or services, and is there a real likelihood that a customer would confuse the two or assume some connection between them.

A few practical signals worth distinguishing:

Same or adjacent market, not just a similar name. A similar word mark in a completely unrelated field is a weaker case than a near-identical mark in your own category.
Registered use vs. unregistered use. Infringement is the statutory claim available because your mark is registered. If the conflicting use involves an unregistered mark trading on similar goodwill, a passing off claim may be the relevant tool instead, or alongside it.
Where it shows up. E-commerce listings, storefronts, company names, packaging, and social handles are where infringing use tends to surface first — often before it shows up as a new Registry filing at all.

If you're not actively watching for these signals on an ongoing basis, see our guide to trademark monitoring and watch services — this guide assumes you've already found something and need to know what to do about it.

Sending a cease-and-desist letter

For most infringement situations, a cease-and-desist letter — not a lawsuit — is the first and often the only step required. It's a formal written demand, sent on your behalf, that establishes your registered rights, identifies the specific infringing use, and requires a response within a set deadline. A well-drafted one resolves a meaningful share of disputes without escalating further, simply because most infringers stop once they understand the registration is real and the demand is credible.

A cease-and-desist letter isn't a form template with your details swapped in — it needs to cite your actual registration, describe the infringing use accurately, and set out what happens if it continues. If it's ignored or rejected, the next step is a considered decision about formal infringement litigation, not an automatic escalation.

Opposing a new conflicting application

Owning a registration doesn't mean no one else can file something similar — it means you have the right to stop them, provided you catch it in time. If monitoring turns up a new third-party application that conflicts with your registered mark, opposition is available on the same terms as during your own filing: a four-month window from journal publication, non-extendable. Catching it inside that window is meaningfully easier than the alternative — contesting an already-registered mark through rectification or cancellation once the window has closed.

Maintaining active use — avoiding non-use cancellation

A registration can become vulnerable to cancellation if a mark goes unused for an extended period — broadly, around 5 years — but this isn't something the Registry polices on its own. Nothing happens automatically. A third party has to actively file to challenge the registration on non-use grounds, and even then, the usage-verification process itself typically takes about a year to resolve.

This isn't a reason to panic over a temporary lull in using a mark in one class among several. It's a reason to keep basic evidence of ongoing use — invoices, marketing materials, packaging, e-commerce listings — as a normal part of how an active business already operates, particularly for classes you registered defensively but use less actively than your core one.

Who actually handles enforcement

If a cease-and-desist letter, an opposition against a new conflicting filing, or a response to a non-use challenge becomes necessary, it's handled by the same named advocate accountable for your case throughout — not handed off to a separate litigation team partway through. You'll always know exactly who's handling it, and the price for that work is agreed with you in writing before it begins.

Get help with an objection or opposition

Detecting a conflict in the first place is covered in our guide to trademark monitoring and watch services. For how enforcement fits alongside renewal and the rest of what a registration actually requires over time, see the full trademark lifecycle and our complete guide to renewal. For the mechanics of opposition itself, see our complete guide to opposition proceedings.