Can foreign application claims the benefit from the US application (wherein US application is claiming priority from provisional application).

Note: 1) US application does not have any child and divisional 2) Foreign application, US application and provisional application published within the 12 months.

If foreign application claims benefit from the US application, does it break some law or US provisional become prior art for foreign application.


  • I fear I can't quite follow your timings. It appears that you're asking whether you can claim priority after publication (which typically occurs at 18 months, well after the priority period ends). Would you be able to include an explicit timeline of when the US provisional, and US non-provisional are filed, with dates for the different events?
    – Maca
    Mar 29, 2017 at 9:53
  • US provisional - 1 Jan 2010 | US application(claiming the priority of US provisional) - 1 July 2010 | WO application(claiming the priority of US application) - 1 sep 2010. Please edit my question if there is some issue. Thanks in advance
    Mar 29, 2017 at 10:02
  • WO1999052812A1 is the best example for this question. but i m convinced how is it possible.
    Mar 29, 2017 at 10:03

1 Answer 1


Priority claims are governed by the Paris Convention art 4.

Arts 4(C)(1)–(2) requires that priority can be claimed for twelve months from the date of filing the first application.

Art 4(C)(4) provides that a subsequent application can only be used if the first filing "has been withdrawn, abandoned, or refused, without having been laid open to public inspection and without leaving any rights outstanding, and if it has not yet served as a basis for claiming a right of priority".

Thus given your example timeline:

1 Jan 2010: US provisional

1 Jul 2010: US non-provisional (claiming the priority of US provisional)

1 Sep 2010: WO application (claiming the priority of US non-provisional)

The WO application could validly claim priority from the US provisional (up until 1 Jan 2011, 12 months from the first filing). It could also claim priority from the US non-provisional (again, up until 1 Jan 2011, 12 months from the first filing). Since the WO was filed within this period, it has a valid priority claim.

The curious case of WO 1999/052812

You mentioned this case in your comment. The family timeframe of this appears to be:

22 April 1997: Provisional US 60/044588 was filed.

16 April 1998: Non-provisional US 09/061823 was filed (which is seemingly identical to the provisional).

12 April 1999: WO 1999/052812 is filed, claiming priority to US 09/061823.

This appears to be a clear case of an invalid priority claim.

The provisional could be used for priority only until 22 April 1998 (12 months from filing). Since the non-provisional has the same subject matter, and the provisional wasn't first abandoned, the non-provisional doesn't reset the clock. The WO filing therefore could only claim priority (to the provisional or the non-provisional) until 22 April 1998. Since it was filed in 1999, it is well beyond the priority period, and thus has an invalid priority claim.

This doesn't seem to have been noted by the USPTO (acting as ISA on the WO) or the EPO (in the subsequent EP regional phase). I can only speculate why, but I presume it's simply because nobody noticed.

  • In EP they usually check only formal requirements. Whether or not a priority claim is valid, will be dealt with in the examination phase and if it actually matters to the patentability of the claims. This was a straightforward case, with no close prior art (only A documents in search report), so it wouldn't really matter. Mar 30, 2017 at 7:57
  • @chempatent1981 can you please elaborate a little?
    Mar 31, 2017 at 5:40
  • 1
    The staff that receives the patent application deals with formal issues. They see a document with a number and a date (the priority doc), they check if those two correspond to the priority claim, they check if any translation is required and that's it. They can easily miss the fact that the priority document mentions the existence of a provisional. However, the examiner will check the validity of the priority claim, if this important to the patentability. In this case, however, there was no close prior art, so it didn't matter anyway and perhaps the examiner just ignored it. Mar 31, 2017 at 6:04

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