Patent Law Alert -- USPTO Requires Foreign‑Domiciled Patent Applicants And Patent Owners To Be Represented By Registered U.S. Patent Counsel

The U.S. Patent and Trademark Office (USPTO) has issued a final patent rule amending the Rules of Practice in Patent Cases to require that patent applicants and patent owners, whose domicile is not located within the United States or its territories, be represented by a registered U.S. patent practitioner. The final rule was published in the Federal Register on March 20, 2026, and takes effect 120 days later, on July 18, 2026.

According to the USPTO, this change is intended to align U.S. patent practice with that of most other major patent offices worldwide, which generally require foreign applicants and patent owners to act through locally licensed representatives. The USPTO has further stated that this rule is designed to improve processing efficiency and to strengthen the Office’s ability to enforce compliance with U.S. statutory and regulatory requirements, including addressing false certifications, misrepresentations, and fraud in patent filings.

Scope of the Requirement

This change affects both patent applicants and patent owners. Foreign‑domiciled applicants may no longer prosecute U.S. patent applications on their own. Foreign‑domiciled patent owners likewise may not take certain post‑issuance actions before the USPTO without representation by a registered U.S. patent attorney or patent agent.

Although an application that otherwise meets the minimum requirements for receipt may still be given a filing date without counsel, the USPTO has made clear that amendments, responses, information disclosure statements, petitions, and other substantive filings generally will not be entered or considered unless they are signed by a registered U.S. practitioner once the rule becomes effective.

Domicile Determination

This rule provides an express definition of “domicile.” For a natural person, domicile refers to the individual’s permanent legal place of residence. For a company or other juristic entity, domicile refers to the entity’s principal place of business. In determining domicile, the USPTO will typically rely on information provided in documents filed with the Office, including application data sheets and inventor declarations, and may consult additional sources, if necessary. The USPTO expressly declined to create exceptions for applications or patents involving mixed‑domicile parties; if any applicant or patent owner is foreign‑domiciled, representation by registered U.S. patent counsel is required.

Similar Trademark Rule

Since August 3, 2019, a similar requirement has applied to U.S. trademark applications and registrations. The USPTO trademark rule requires a domicile address for all trademark filers (foreign and domestic), and it also requires foreign-domiciled trademark applicants and registrants to have a U.S.-licensed attorney.

Practical Implications and Practice Tips

Because this patent rule applies not only to pending applications but also to issued patents, foreign‑domiciled patent owners should carefully review their U.S. patent portfolios to identify matters that may require action on or after the effective date, including maintenance‑related filings, office‑action responses, and post‑grant petitions. Failure to comply with the U.S. representation requirement may result in papers not being entered or considered by the USPTO, with potentially significant consequences for application pendency or the status of issued patents.

As a practical matter, foreign applicants and patent owners should consider engaging U.S. patent counsel well in advance of the effective date to avoid disruptions to prosecution or post‑grant administration. Companies may also wish to review internal procedures related to the preparation of application data sheets and certifications, as inaccuracies in domicile information may receive heightened scrutiny under the new rule.

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