Patent Law FAQ

The deadline for filing an unintentionally delayed priority claim is the later of:

• Four months from the actual filing date of the later-filed application, or
• Sixteen months from the filing date of the prior application

This is stated in 37 CFR 1.55(d)(1) for foreign priority claims and 37 CFR 1.78(a)(4) for domestic benefit claims. However, a petition may be filed to accept an unintentionally delayed claim under 37 CFR 1.55(e) or 37 CFR 1.78(c) and (e) after this period.

As stated in MPEP 214.02: ‘A petition to accept an unintentionally delayed claim for priority under 35 U.S.C. 119(a)-(d) or (f), 365(a) or (b), or 386(a) or 386(b) requires:’

• The priority claim under 35 U.S.C. 119(a)-(d) or (f), 365(a) or (b), or 386(a) or 386(b) in an application data sheet (§ 1.76(b)(6)), identifying the foreign application for which priority is claimed, by specifying the application number, country (or intellectual property authority), day, month, and year of its filing, unless previously submitted;
• The petition fee as set forth in § 1.17(m); and
• A statement that the entire delay between the date the priority claim was due and the date the priority claim was filed was unintentional.

To learn more:

• unintentionally delayed priority claim
• deadline
• petition
• 37 CFR 1.55
• 37 CFR 1.78

To learn more:

• 37 CFR 1.55
• 37 CFR 1.78