When you claim priority to an earlier application in a foreign or PCT filing, the receiving office needs proof of that earlier application — a certified copy known as a priority document. It's a routine requirement with an unforgiving deadline, and the most common way it goes wrong is simply waiting too long to request it. Here's what you need to know.
What a Priority Document Is
Under the Paris Convention, an applicant can claim the filing date of an earlier application (the "priority date") in later filings abroad, as long as they're made within the priority period. To perfect that claim, the later office requires a certified copy of the original application — the priority document — issued by the office where the first application was filed. For a U.S.-origin application, that's a certified copy from the USPTO.
Mind the Deadline
Priority documents are deadline-driven. In the PCT system, for example, the certified copy generally must be furnished within 16 months of the priority date. Miss it, and you can lose the benefit of your earlier filing date — which can be fatal to patentability if anything was disclosed in the interim. Because the deadline is fixed and processing takes time, this is not something to leave until the last week.
How to Obtain One
- Certified copy from the USPTO. Request a certified copy of the priority application from the USPTO's Certification Branch. Note that current processing times can be lengthy, so order well ahead of the deadline.
- Electronic exchange (WIPO DAS). In many cases the priority document can be exchanged electronically through the WIPO Digital Access Service, avoiding a paper certified copy — when the offices involved participate.
Don't Let Processing Time Cost You the Date
As of mid-2026, the USPTO Certification Branch is taking roughly 90 days to process certified copy requests — though we've been told to expect those times to decrease over the coming months as the office adds staff, which we covered in our recent Certification Branch update. Given the current timeline, request the priority document as early as possible rather than close to the deadline. To get an idea of the cost and processing time for your specific request, enter your details in our free estimate tool.
We Obtain Priority Documents for You
We request certified copies — including priority documents — from the USPTO every day and track them against your deadlines. We can also provide high-resolution color scans of the certified copies for your records and forward the physical originals anywhere in the world — your office, your foreign associate, or directly to the receiving office. If you need a certified priority document for a foreign or PCT filing, see our certified copy services or reach out to our team.
The Patent Place specializes in obtaining certified documents from the USPTO and legalizing intellectual property documents for use in countries around the world.