Ley Federal de Protección a la Propiedad Industrial art. 221 gives one months from publication of the application. The window is not extendable, and it does not restart.
We hold this window as indicative rather than pinned to its provision with the confidence we apply elsewhere. Treat it as the shape of the deadline, not the deadline — local counsel confirms it before you act.
The application is examined first, then published. The clock starts at publication. Counting from the filing date makes you early, which is harmless; counting from registration makes you late, which is not.
Mexico opens the window at publication of the application, as most offices do. But Switzerland, Germany, Japan and Sweden register the mark first and run opposition from publication of the registration.
Applying one office’s rule to another does not shift a deadline by a few days. It invents one that never existed — and the real one may already have closed.
Once opposition lapses you are into cancellation or invalidity — a different action, different evidence, more cost, lower odds. Worth knowing early: a holder whose own book is largely lapsed or withdrawn is more vulnerable to a non-use challenge than the register first suggests.
Read from the public registers and the cited provision. Intelligence, not legal advice — your counsel confirms the date and acts on it.