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35 USC § 21 - Filing date and day for taking action 

---
identifier: "/us/usc/t35/s21"
source: "usc"
legal_status: "official_legal_evidence"
title: "35 USC § 21 - Filing date and day for taking action"
title_number: 35
title_name: "PATENTS"
section_number: "21"
section_name: "Filing date and day for taking action"
chapter_number: 2
chapter_name: "PROCEEDINGS IN THE PATENT AND TRADEMARK OFFICE"
part_number: "I"
part_name: "UNITED STATES PATENT AND TRADEMARK OFFICE"
positive_law: true
currency: "119-84"
last_updated: "2025-12-12"
format_version: "1.1.0"
generator: "[email protected]"
source_credit: "(July 19, 1952, ch. 950, 66 Stat. 794; Pub. L. 93–596, § 1, Jan. 2, 1975, 88 Stat. 1949; Pub. L. 97–247, § 12, Aug. 27, 1982, 96 Stat. 321; Pub. L. 106–113, div. B, § 1000(a)(9) [title IV, § 4732(a)(10)(A)], Nov. 29, 1999, 113 Stat. 1536, 1501A–582; Pub. L. 107–273, div. C, title III, § 13206(b)(1)(B), Nov. 2, 2002, 116 Stat. 1906.)"
---

# § 21. Filing date and day for taking action

**(a)** The Director may by rule prescribe that any paper or fee required to be filed in the Patent and Trademark Office will be considered filed in the Office on the date on which it was deposited with the United States Postal Service or would have been deposited with the United States Postal Service but for postal service interruptions or emergencies designated by the Director.

**(b)** When the day, or the last day, for taking any action or paying any fee in the United States Patent and Trademark Office falls on Saturday, Sunday, or a Federal holiday within the District of Columbia, the action may be taken, or the fee paid, on the next succeeding secular or business day.

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**Source Credit**: (July 19, 1952, ch. 950, 66 Stat. 794; Pub. L. 93–596, § 1, Jan. 2, 1975, 88 Stat. 1949; Pub. L. 97–247, § 12, Aug. 27, 1982, 96 Stat. 321; Pub. L. 106–113, div. B, § 1000(a)(9) [title IV, § 4732(a)(10)(A)], Nov. 29, 1999, 113 Stat. 1536, 1501A–582; Pub. L. 107–273, div. C, title III, § 13206(b)(1)(B), Nov. 2, 2002, 116 Stat. 1906.)

### Historical and Revision Notes

Based on Title 35, U.S.C., 1946 ed., § 21 (, ).

“Fixed by statute” is omitted from the corresponding section of the existing statute as unnecessary. Saturday is added as a day on which action need not be taken.

## Editorial Notes

### Amendments

2002—Subsec. (a).  made technical correction to directory language of . See 1999 Amendment note below.

1999—Subsec. (a). , as amended by , substituted “Director” for “Commissioner” in two places.

1982— substituted “Filing date and day for taking action” for “Day for taking action falling on Saturday, Sunday, or holiday” as section catchline, added subsec. (a), redesignated existing provisions as subsec. (b) and inserted “Federal” after “Sunday, or a”.

1975— substituted “Patent and Trademark Office” for “Patent Office”.

## Statutory Notes and Related Subsidiaries

### Effective Date of 1999 Amendment

Amendment by  effective 4 months after , see section 1000(a)(9) [title IV, § 4731] of , set out as a note under .

### Effective Date of 1982 Amendment

Amendment by  effective six months after , see , set out as an Effective Date note under .

### Effective Date of 1975 Amendment

Amendment by  effective , see , set out as a note under , Commerce and Trade.

### Emergency Relief From Postal Situation Affecting Patent Cases

Relief as to filing date of patent application or patent and excusal of delayed fees or actions affected by postal situation beginning on , and ending on or about , see note set out under .