Brief summary
- The deadline for responding to a Korean patent office action is the period for submission of a written argument written in the notice. The examiner sets that period within four months.
- The range of “within four months” has applied since 11 July 2025. Before that date, the range was within two months.
- The period for submission of a written argument can be extended in units of one month. Up to four months from the expiration date of the designated period (specified period), a request for extension is deemed approved when it is received.
The period is taken from the Enforcement Rules of the Patent Act (특허법 시행규칙) in force from 14 May 2026. The extension rules are taken from the Regulations for the Handling of Patent and Utility Model Examination Affairs (특허·실용신안 심사사무취급규정) in force from 1 July 2026. Last verified on 8 October 2026.
Last verified
Deadline and extensions at a glance
As of October 2026.
| Item | Rule | Basis |
|---|---|---|
| Period for submission of a written argument | Designated by the examiner within 4 months | Patent Act, Art. 63(1); Enforcement Rules, Art. 16(1), subparagraph 2 |
| Range until 10 July 2025 | Within 2 months | Enforcement Rules, Art. 16(1), before the amendment |
| Unit of extension | 1 month at a time; several months can be requested at once | Handling Regulations, Art. 23(2) |
| Extension approved without examination of the reasons | Up to 4 months from the expiration date of the designated period | Handling Regulations, Art. 23(3) |
| Extension after that | Only the period that the examiner finds necessary | Handling Regulations, Art. 23(4) and (5) |
| Extension fee | KRW 20,000 for the first month, KRW 30,000 for the second, KRW 60,000 for the third, KRW 120,000 for the fourth, then KRW 240,000 for each month | Fee Regulation, Art. 2(1), subparagraph 13-2 |
| Shortening of the period | On request, the period is deemed to have ended on the date the request is filed | Patent Act, Art. 15(2); Examination Guidelines, Part 1, Chapter 3, 4.4 |
| Decision of rejection after no response within the period | Request for re-examination or petition for trial within 3 months from the date on which the certified copy of the decision is served | Patent Act, Arts. 67-2 and 132-17 |
The Patent Act (특허법) calls this notice a “notice of grounds for rejection” (거절이유통지). [1] The document that the applicant receives is titled “Notice of Preliminary Rejection” (의견제출통지서). [5] This article uses the two terms with the same meaning.
The examiner sets the deadline within four months
The deadline for responding to a Korean patent office action is not a period fixed by statute. It is a designated period set by the examiner. Article 63(1) of the Patent Act provides that the examiner notifies the grounds for rejection and gives the applicant an opportunity to submit a written argument within a designated period. [1]
The upper limit of that period is in Article 16(1), subparagraph 2 of the Enforcement Rules of the Patent Act. The examiner must set the period for submission of a written argument under Article 63(1) of the Patent Act within four months. [2] Article 23(1) of the Regulations for the Handling of Patent and Utility Model Examination Affairs sets the same range. [4]
The Patent Examination Guidelines (특허·실용신안 심사기준) state that the period for submission of a written argument is normally designated within four months. [5] The Examination Guidelines also state that this range is the same whether or not the applicant is an overseas resident (a person with no domicile or place of business in Korea). [5] The actual deadline must be checked in each case from the date written in the notice.
A procedure that needs time for a test or for measuring results is an exception. In that case, the designated period is the time that the test and measurement take (proviso to Enforcement Rules, Art. 16(1)). [2]
Before 11 July 2025, the range was within two months
The range of the period for submission of a written argument was extended from within two months to within four months by the amendment in force from 11 July 2025. [2] Before the amendment, Article 16(1) of the Enforcement Rules set the period for submission of a written argument within two months. [2]
The Addenda to the amended Enforcement Rules consist of one sentence: the Rules enter into force on the date of promulgation. There is no applicability provision and no transitional measure. [2] Article 23(1) of the Handling Regulations was amended on the same day, 11 July 2025. [4]
Article 16(1) of the Enforcement Rules sets the range that the examiner must observe when setting a period. [2] The Addenda to the amended Enforcement Rules contain no provision that changes a period already designated. [2] Materials that state a two-month period follow the rule before the amendment.
The period is counted from the day after the notice is received
The first day of a period is not counted (Patent Act, Art. 14, subparagraph 1). [1] The period starts on the day after the notice is served. [5]
A period in months is calculated by the calendar. It ends on the day before the day in the last month that corresponds to the starting day (Patent Act, Art. 14, subparagraphs 2 and 3). [1] If the last month has no corresponding day, the period ends on the last day of that month. [1]
If the last day of the period is a public holiday, the period ends on the following day. Saturdays and Workers’ Day (노동절) are included in public holidays (Patent Act, Art. 14, subparagraph 4). [1]
Extensions are in one-month units and are approved on receipt up to four months
The period for submission of a written argument can be extended at the request of the applicant (Patent Act, Art. 15(2)). [1] The request is made with the request for extension of the period in Form 10 of the Enforcement Rules of the Patent Act (Enforcement Rules, Art. 16(2)). [2]
Extensions are in units of one month. Several months can be requested at once, and a period requested for less than one month is treated as one month (Handling Regulations, Art. 23(2)). [4]
In some cases the requested extension ends within four months from the expiration date of the designated period. In these cases, the request for extension is deemed approved when it is received (Handling Regulations, Art. 23(3)). [4] The Examination Guidelines state that the reasons for extension are examined only for requests that go beyond this range. [5]
For the part beyond four months, the examiner looks at the reasons and decides whether to approve. [4] The Examination Guidelines give the following seven grounds. [5]
| No. | Ground on which an extension beyond four months may be approved |
|---|---|
| 1 | An agent was appointed for the first time, or all agents were dismissed or changed, within 1 month before the expiration of the period |
| 2 | A notice of change of applicant was filed within 1 month before the expiration of the period and a new applicant was added |
| 3 | An examination result of a foreign patent office was received within 2 months before the expiration of the period and is filed together with the request for extension of the period |
| 4 | Service of the Notice of Preliminary Rejection was delayed by 1 month or more |
| 5 | The original application (parent application) or a later-filed application is pending in a trial or in litigation |
| 6 | A test and measurement of results related to the grounds for rejection need more time |
| 7 | An extension is otherwise found to be unavoidably necessary |
For an application in which a third party requested examination, an extension beyond four months is not approved even on grounds 1 to 5. [5]
The examiner must decide whether to approve a request for extension of the period beyond four months within two weeks from the date on which the request was transferred to the examiner (Handling Regulations, Art. 23-2). [4]
A request for extension must be filed before the period ends. A request for extension of the period filed after the designated period has passed is returned after the applicant has been given an opportunity to explain. [5]
The extension fee rises with each month
The extension fee for a designated period differs for each part of the extension period (Regulation on the Collection of Patent Fees, etc. (특허료 등의 징수규칙), Art. 2(1), subparagraph 13-2). [3] The Fee Regulation attaches the amount to each part of the extension period, not to the number of requests. [3]
| Part of the extension period | Fee for that part | Total for an extension up to that part |
|---|---|---|
| Up to 1 month | KRW 20,000 | KRW 20,000 |
| Over 1 month and up to 2 months | KRW 30,000 | KRW 50,000 |
| Over 2 months and up to 3 months | KRW 60,000 | KRW 110,000 |
| Over 3 months and up to 4 months | KRW 120,000 | KRW 230,000 |
| Over 4 months | KRW 240,000 for each month | KRW 470,000 for 5 months |
The amounts for each part were set by the amendment in force from 1 January 2013. [3]
If the extension fee is not paid, the applicant receives a request for amendment. If the fee is not paid within the period designated there, the request for extension is invalidated. [5] If the request for extension is not approved or is returned, the official fee paid is refunded. [5]
The period for submission of a written argument is also the period for amendment
After a notice of grounds for rejection, the specification and drawings can be amended only within the period for submission of a written argument under that notice (Patent Act, Art. 47(1)). [1] The period for submission of a written argument can be extended by a request for extension of the designated period. [5]
If several amendments are filed in the same period, all amendments before the last amendment are deemed withdrawn (Patent Act, Art. 47(4)). [1]
If no written argument and no written amendment are filed within the period, the examiner can examine the application again and issue a decision of rejection (decision to reject a patent application). [4] Article 62 of the Patent Act provides that the examiner issues a decision of rejection for an application that has a ground for rejection. [1]
An applicant who has received a decision of rejection can request re-examination within three months from the date on which a certified copy of the decision was served. Re-examination is requested together with an amendment of the specification or drawings (Patent Act, Art. 67-2(1)). [1] Within the same three months, the applicant can also file an appeal against the examiner’s decision to reject a patent application (trial on rulings rejecting patent applications) under Article 132-17 of the Patent Act. [1] The period for filing a petition for trial can be extended once, by up to 30 days (Patent Act, Art. 15(1)). [1]
The procedure after a missed deadline is covered in a separate article in this series.
The period can be shortened to obtain a decision sooner
A designated period can also be shortened at the request of the applicant (Patent Act, Art. 15(2)). [1] The applicant files a request for shortening of the period or states the intention to shorten the period in the written amendment (Enforcement Rules, Art. 16(2)). [2]
When shortening is requested, the designated period is deemed to have ended on the date that request or written amendment is filed. The examiner proceeds with examination without waiting for the rest of the period. [5] The Fee Regulation has no fee item for shortening a designated period. Form 10 also provides that the fee field is deleted in a request for shortening. [2][3]
Example: a notice received on 10 November 2026
The schedule assumes that a notice with a period for submission of a written argument designated as four months was served on 10 November 2026. Temporary public holidays are not taken into account.
| Step | Calculated expiration date | Last day on which filing is actually possible | Total extension fee |
|---|---|---|---|
| Designated period (4 months) | 10 March 2027 (Wed) | 10 March 2027 | None |
| 1-month extension | 10 April 2027 (Sat) | 12 April 2027 (Mon) | KRW 20,000 |
| 2-month extension | 10 May 2027 (Mon) | 10 May 2027 | KRW 50,000 |
| 3-month extension | 10 June 2027 (Thu) | 10 June 2027 | KRW 110,000 |
| 4-month extension | 10 July 2027 (Sat) | 12 July 2027 (Mon) | KRW 230,000 |
The period starts on 11 November 2026, the day after service. [1] The four-month designated period ends on 10 March 2027.
An extension period is counted from the day after the previous period ended. This is the same when the last day of the previous period is a public holiday. [5] The two-month extension therefore ends on 10 May, not on 12 May.
The extension that is approved without examination of the reasons runs until 10 July 2027, four months from the expiration date of the designated period. [4] An extension after that needs the approval of the examiner and costs KRW 240,000 for each month. [3][4]
How Korea differs
The Korean Handling Regulations do not set a numerical upper limit on the total period including extensions. [4] The US rule provides that an extension cannot go beyond the maximum period set by statute. [6]
| Office | Period set in the notice | Extension | Basis |
|---|---|---|---|
| Korea | Designated by the examiner within 4 months | In 1-month units. Approved on receipt up to 4 months from the expiration date of the designated period. After that, approval of the examiner | Enforcement Rules in force from 14 May 2026; Handling Regulations in force from 1 July 2026 |
| United States | The period set in the notice. A maximum of 6 months unless a period shorter than 6 months is notified in writing | By petition and fee, up to 5 months after the period set. Cannot go beyond the maximum period set by statute | 37 CFR 1.134, 1.136(a) [6] |
| Europe (EPO) | Not less than 2 months and not more than 4 months. Up to 6 months in certain circumstances | Extended in special cases on a request filed before the expiry of the period | Rule 132(2) EPC [7] |
US 37 CFR 1.134 provides that a maximum of six months is allowed unless a shorter period is notified in writing. [6] In Korea, an extension beyond four months is also approved if the examiner finds it necessary. [4]
Europe limits extensions to “special cases” (Rule 132(2) EPC). [7] Korea approves an extension on receipt of the request alone, up to four months from the expiration date of the designated period. [4]
What applicants should do
- In general, we suggest checking the due date written in the notice first when a notice is received. The designated period is set by the examiner in each case.
- If an extension is needed, we suggest requesting it before the period ends. A request for extension filed after the period has passed is returned.
- The extension fee rises sharply from the fourth month. It is better to request only as many months as the response needs.
- Approval of an extension beyond four months is not guaranteed. We suggest planning the schedule within four months from the expiration date of the designated period.
- For an application where early registration matters, it is worth considering a statement of the intention to shorten the period in the written amendment.
- The deadline in an individual case must be confirmed with your Korean agent.
FAQ
Is the deadline for responding to a Korean office action two months or four months?
Since 11 July 2025, the examiner sets the period for submission of a written argument within four months. [2] Before that date, the range was within two months. [2] The deadline in a given case is the date written in the notice.
How many times can the period be extended?
The Handling Regulations limit extensions by period, not by the number of requests. Extensions are requested in units of one month, and they are approved on receipt up to four months from the expiration date of the designated period. [4] After that, an extension is approved only if the examiner finds it necessary. [4]
What happens if the deadline falls on a Saturday or a public holiday?
The period ends on the following day. Saturdays and Workers’ Day are also treated as public holidays (Patent Act, Art. 14, subparagraph 4). [1]
Can an extension be requested after the deadline has passed?
No. A request for extension of the period filed after the designated period has passed is returned after the applicant has been given an opportunity to explain, and the official fee is refunded. [5]
If two written amendments are filed within the period, which one remains?
The last amendment remains. All earlier amendments are deemed withdrawn (Patent Act, Art. 47(4)). [1]
How DEFINE IP Law Firm handles this
DEFINE IP Law Firm checks the due date and the last day to which the period can be extended at the stage when a Notice of Preliminary Rejection is received. We decide with the applicant whether to extend, together with the direction of the response. For questions about deadlines for Korean office actions, please write to contact@defineip.kr.
Sources
- Patent Act (특허법), Act No. 21134, in force from 11 November 2025. Articles 14, 15, 47, 62, 63, 67-2 and 132-17. https://www.law.go.kr/법령/특허법 (verified 8 October 2026)
- Enforcement Rules of the Patent Act (특허법 시행규칙), Prime Ministerial Decree No. 2115, in force from 14 May 2026. Article 16, Form 10. The content before the amendment is that of the version in force from 1 November 2024 (Ordinance of the Ministry of Trade, Industry and Energy (산업통상자원부령) No. 579). The amendment is Ordinance of the Ministry of Trade, Industry and Energy No. 609 (in force from 11 July 2025) and its Addenda. https://www.law.go.kr/법령/특허법시행규칙 (verified 8 October 2026)
- Regulation on the Collection of Patent Fees, etc. (특허료 등의 징수규칙), Prime Ministerial Decree No. 2098, in force from 27 February 2026. Art. 2(1), subparagraph 13-2. The amounts for each part of the extension period were introduced by Ordinance of the Ministry of Knowledge Economy (지식경제부령) No. 280 (in force from 1 January 2013). https://www.law.go.kr/법령/특허료등의징수규칙 (verified 8 October 2026)
- Ministry of Intellectual Property (지식재산처), Regulations for the Handling of Patent and Utility Model Examination Affairs (특허·실용신안 심사사무취급규정), MOIP Directive (지식재산처훈령) No. 41, in force from 1 July 2026. Articles 23, 23-2 and 26(3). https://www.law.go.kr/행정규칙/특허·실용신안심사사무취급규정 (verified 8 October 2026)
- Ministry of Intellectual Property (지식재산처), Patent Examination Guidelines (특허·실용신안 심사기준), MOIP Established Rule (지식재산처예규) No. 7, in force from 13 March 2026. Part 1, Chapter 3 “Period”; Part 4, Chapter 1, 4.2; Part 5, Chapter 3, 5.; Part 5, Chapter 3, 6.1. https://www.law.go.kr/행정규칙/특허·실용신안심사기준 (verified 8 October 2026)
- US Code of Federal Regulations, 37 CFR 1.134 and 1.136, eCFR version as of 6 October 2026. https://www.ecfr.gov/current/title-37/section-1.134 (verified 8 October 2026)
- EPO, Rule 132 EPC (European Patent Convention, 2020 edition), no publication date shown. https://www.epo.org/en/legal/epc/2020/r132.html (verified 8 October 2026)