Guide

New prior art raising a substantial question about a granted patent: request re-examination of its claims

New prior art raising a substantial question about a granted patent: request re-examination of its claims

Priority

A requester other than the patentee does not participate after filing and cannot appeal refusal to appoint a board. Assess that choice before filing.

Confirm the scope

Check that the patent is eligible and in force and identify the exact claims and substantial new question of patentability.

Prepare the information

Gather prior patents, laid-open applications or printed publications and explain relevance without relying on inadmissible evidence.

Complete the process

Prepare the re-examination request, patent number, claim-by-claim analysis and fee, then file through MyCIPO.

Keep follow-up records

Follow the board-appointment decision; if you are the patentee, respond and assess appeal from any cancellation or amendment.

Re-examination of a granted patent — CIPO

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Official sources are linked in the guide. Checked August 30, 2026; confirm current rules, forms and deadlines with the responsible authority.
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