# MPEP § 1801: Basic Patent Cooperation Treaty (PCT) Principles

> Federal · Agency guidance · In force

URL: https://www.frixlaw.com/law-library/statutes/MPEP_S1801

## Section

- **Citation:** MPEP § 1801
- **Heading:** Basic Patent Cooperation Treaty (PCT) Principles
- **Jurisdiction:** Federal
- **Kind:** Agency guidance
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** USPTO MPEP / Chapter 1800 - Patent Cooperation Treaty / MPEP § 1801

## Text

I.
MAJOR CONCEPTS OF THE PCT
The Patent Cooperation Treaty (PCT) enables the U.S. applicant to
file one application, “an international application,” in a standardized format in
English in the U.S. Receiving Office (the U.S. Patent and Trademark Office), and
have that application acknowledged as a regular national or regional filing in as
many Contracting States to the PCT as the applicant “designates,” i.e., names, as
countries or regions in which patent protection is desired. The filing of an
international application will automatically constitute the designation of all
contracting countries to the PCT on that filing date. In the same manner, the PCT
enables foreign applicants to file a PCT international application, designating the
United States of America, in their home language in their home patent office and
have the application acknowledged as a regular U.S. national filing. The PCT also
provides for the establishment of an international search report and written opinion
at 16 months from the priority date and publication of the international application
after 18 months from the priority date. Upon payment of national fees and the
furnishing of any required translation, usually 30 months after the filing of any
priority application for the invention, or the international filing date if no
priority is claimed, the application will be subjected to national procedures for
granting of patents in each of the designated countries. For any countries remaining
whose national laws are not compatible with the 30 month period set forth in
PCT Article
22(1)
, the filing of a demand for an international
preliminary examination electing such countries within 19 months from the priority
date will result in an extension of the period for entering the national stage to 30
months from the priority date. An up-to-date list of such countries may be found on
WIPO’s website (
www.wipo.int/ pct/en/texts/reservations/res_incomp.html
). See
also subsection V. below
the filing of a demand for an international
preliminary examination electing such countries within 19 months from the priority
date will result in an extension of the period for entering the national stage to 30
months from the priority date. An up-to-date list of such countries may be found on
WIPO’s website (
www.wipo.int/ pct/en/texts/reservations/res_incomp.html
). See
also subsection V. below. A brief description of the basic flow under the PCT is
provided in
MPEP §
1842
.
The PCT offers an alternative route to filing patent applications
directly in the patent offices of those countries which are Contracting States of
the PCT. It does not preclude taking advantage of the priority rights and other
advantages provided under the Paris Convention and the WTO administered Agreement on
Trade-Related Aspects of Intellectual Property (TRIPS Agreement). The PCT provides
an additional and optional foreign filing route to patent applicants.
The filing, search and publication procedures are provided for in
Chapter I of the PCT. Additional procedures for a preliminary examination of PCT
international applications are provided for in optional PCT Chapter II.
In most instances, a national U.S. application is filed first. An
international application for the same subject matter will then be filed
subsequently within the priority year provided by the Paris Convention and the
priority benefit of the U.S. national application filing date will be claimed.
II.
RECEIVING OFFICE (RO)
The international application (IA) must be filed in the prescribed
receiving Office (RO)(
PCT Article 10
). The United
States Patent and Trademark Office will act as a receiving Office for United States
residents and nationals (
35 U.S.C. 361(a)
). Under
PCT Rule
19.1(a)(iii)
, the International Bureau of the World
Intellectual Property Organization will also act as a Receiving Office for U.S.
residents and nationals. The receiving Office functions as the filing and
formalities review organization for international applications
and Trademark Office will act as a receiving Office for United States
residents and nationals (
35 U.S.C. 361(a)
). Under
PCT Rule
19.1(a)(iii)
, the International Bureau of the World
Intellectual Property Organization will also act as a Receiving Office for U.S.
residents and nationals. The receiving Office functions as the filing and
formalities review organization for international applications. International
applications must contain upon filing the designation of at least one Contracting
State in which patent protection is desired and must meet certain standards for
completeness and formality (
PCT Articles 11(1)
and
14(1)
).
Where a priority claim is made, the date of the earliest-filed
application whose priority is claimed is used as the date for determining the timing
of international processing, including the various transmittals, the payment of
certain international and national fees, and publication of the application. Where
no priority claim is made, the international filing date will be considered to be
the “priority date” for timing purposes (
PCT Article 2(xi)
).
The international application is subject to the payment of certain
fees within 1 month from the date of receipt. See
PCT Rules
14.1(c)
,
15.3
, and
16.1(f)
. The
receiving Office will grant an international filing date to the application, collect
fees, handle informalities by direct communication with the applicant, and monitor
all corrections (
35 U.S.C. 361(d)
). By 13 months from the priority date, the
receiving Office should prepare and transmit a copy of the international
application, called the search copy (SC), to the International Searching Authority
(ISA); and forward the original, called the record copy (RC), to the International
Bureau (IB) (
PCT
Rules 22.1
and
23
). A second copy of the
international application, the home copy (HC), remains in the receiving Office
(
PCT Article
12(1)
)
receiving Office should prepare and transmit a copy of the international
application, called the search copy (SC), to the International Searching Authority
(ISA); and forward the original, called the record copy (RC), to the International
Bureau (IB) (
PCT
Rules 22.1
and
23
). A second copy of the
international application, the home copy (HC), remains in the receiving Office
(
PCT Article
12(1)
). Once the receiving Office has transmitted copies of
the application, the International Searching Authority becomes the focus of
international processing.
III.
INTERNATIONAL SEARCHING AUTHORITY (ISA)
The basic functions of the International Searching Authority (ISA)
are to conduct a prior art search of inventions claimed in international
applications (it does this by searching in at least the minimum documentation
defined by the Treaty (
PCT Articles 15
and
16
and
PCT Rule 34
)) and to issue a
written opinion (
PCT Rule 43bis
) which will normally be considered to be the first written
opinion of the International Preliminary Examining Authority where international
preliminary examination is demanded. See
PCT Rule
66.1bis
.
For most applications filed with the United States Receiving
Office, the applicant may choose (in the Request form) the U.S. Patent and Trademark
Office, the European Patent Office, the Korean Intellectual Property Office, the
Australian Patent Office (IP Australia), the Israel Patent Office (ILPO), the Japan
Patent Office (JPO), or the Intellectual Property Office of Singapore (IPOS) to act
as the International Searching Authority. However, IP Australia and JPO may not be
competent to act as an International Searching Authority for certain applications
filed by nationals or residents of the United States. See
MPEP §§ 1840.01
-
1840.07
. The International Searching Authority is also
responsible for checking the content of the title and abstract (
PCT Rules
37.2
and
38.2
)
IPOS) to act
as the International Searching Authority. However, IP Australia and JPO may not be
competent to act as an International Searching Authority for certain applications
filed by nationals or residents of the United States. See
MPEP §§ 1840.01
-
1840.07
. The International Searching Authority is also
responsible for checking the content of the title and abstract (
PCT Rules
37.2
and
38.2
).
An international search report (ISR) and written opinion will
normally be issued by the International Searching Authority within 3 months from the
receipt of the search copy (usually about 16 months after the priority date)
(
PCT Rule
42
). Copies of the international search report and prior art
cited will be made available to the applicant by the ISA (
PCT Rules 43
and
44.1
). The international search report will contain a
listing of documents found to be relevant and will identify the claims in the
application to which they are pertinent. The written opinion indicates whether each
claim appears to satisfy the
PCT Article 33
criteria of
“novelty,” “inventive step,” and “industrial applicability.” The written opinion may
also indicate defects in the form or content of the international application under
the PCT articles and regulations, as well as any observations the ISA wishes to make
on the clarity of the claims, the description, and the drawings, or on the question
of whether the claims are fully supported by the description.
Once the international search report and written opinion are
established, the ISA transmits one copy of each to the applicant and the
International Bureau, and international processing continues before the
International Bureau. If a Demand for Chapter II examination is not timely filed,
the International Bureau communicates a copy of the written opinion established by
the ISA (retitled International Preliminary Report on Patentability (Chapter I of
the PCT)) to each designated Office after the expiration of 30 months from the
priority date.
IV
ureau, and international processing continues before the
International Bureau. If a Demand for Chapter II examination is not timely filed,
the International Bureau communicates a copy of the written opinion established by
the ISA (retitled International Preliminary Report on Patentability (Chapter I of
the PCT)) to each designated Office after the expiration of 30 months from the
priority date.
IV.
INTERNATIONAL BUREAU (IB)
The basic functions of the International Bureau (IB) are to maintain
the master file of all international applications and to act as the publisher and
central coordinating body under the Treaty. The World Intellectual Property
Organization (WIPO) in Geneva, Switzerland performs the duties of the International
Bureau.
If the applicant has not filed a certified copy of the priority
document in the receiving Office with the international application, requested upon
filing that the receiving Office prepare and transmit to the International Bureau a
copy of the prior U.S. national application, the priority of which is claimed, or
requested the International Bureau to obtain a copy of the earlier application from
a digital library, the applicant must submit such a document directly to the
International Bureau or the receiving Office not later than 16 months after the
priority date (
PCT
Rule 17
). The request (Form PCT/RO/101) contains a box which
can be checked requesting the receiving Office to prepare and transmit a copy of a
prior application. This is only possible, of course, if the receiving Office is a
part of the same national Office where the priority application was filed. The
request (Form PCT/RO/101) also contains a box which can be checked requesting the
International Bureau to obtain a copy of the earlier application from a digital
library
d requesting the receiving Office to prepare and transmit a copy of a
prior application. This is only possible, of course, if the receiving Office is a
part of the same national Office where the priority application was filed. The
request (Form PCT/RO/101) also contains a box which can be checked requesting the
International Bureau to obtain a copy of the earlier application from a digital
library. This is only possible if the application is registered in a digital
library, made available to the International Bureau within the prescribed time
limit, as set forth in
PCT Rule
17.1(b-bis)
, and the access code is
furnished to the International Bureau.
The applicant has normally 2 months from the date of transmittal of
the international search report to amend the claims by filing an amendment and may
file a brief statement explaining the amendment directly with the International
Bureau (
PCT
Article 19
and
PCT Rule 46
). The International
Bureau will then normally publish the international application along with the
search report and any amended claims at the expiration of 18 months from the
priority date (
PCT
Article 21
). For applications filed before July 1, 2014,
former PCT Rule 44
ter
provided that the written opinion of the
ISA would not be made publicly available until the expiration of 30 months from the
priority date. For applications filed on or after July 1, 2014, the written opinion
of the ISA and any informal comments submitted by the applicant are made available
to the public in their original language as of the publication date. The
international publication includes a front page containing bibliographical data, the
abstract, and a figure of the drawing (
PCT Rule 48
). The publication
also contains the search report and any amendments to the claims submitted by the
applicant. If the application is published in a language other than English, the
search report and abstract are also published in English
he publication date. The
international publication includes a front page containing bibliographical data, the
abstract, and a figure of the drawing (
PCT Rule 48
). The publication
also contains the search report and any amendments to the claims submitted by the
applicant. If the application is published in a language other than English, the
search report and abstract are also published in English. The International Bureau
publishes a
PCT Gazette
in the French and English languages which
contains information similar to that on the front pages of published international
applications, as well as various indexes and announcements (
PCT Rule 86
).
The International Bureau also communicates copies of the publication of the
international application to all designated Offices that have requested to receive
the publication (
PCT Article 20
,
PCT Rule 47
, and
PCT Rule
93bis.1)
.
V.
DESIGNATED OFFICE (DO) and ELECTED OFFICE (EO)
The designated Office is the national Office (for example, the
USPTO) acting for the state or region designated under Chapter I. Similarly, the
elected Office is the national Office acting for the state or region elected under
Chapter II.
PCT Article
22(1)
was amended, effective April 1, 2002, to specify that a
copy of the international application, a translation thereof (as prescribed), and
the national fee are due to the designated Office not later than at the expiration
of 30 months from the priority date. Accordingly, the time period for filing the
copy of the international application, the translation, and the fee under
PCT Article
22
is the same as the 30 month time period set forth in
PCT Article
39
. The USPTO has adopted the 30 month time limit set forth
in
PCT Article
22(1)
. Most Contracting States have changed their national
laws for consistency with
PCT Article 22(1)
as amended.
An up-to-date listing of Contracting States that have adopted
Article 22(1)
as amended is maintained at WIPO’s website at
www.wipo.int/pct/en/texts/ time_limits.html
onth time period set forth in
PCT Article
39
. The USPTO has adopted the 30 month time limit set forth
in
PCT Article
22(1)
. Most Contracting States have changed their national
laws for consistency with
PCT Article 22(1)
as amended.
An up-to-date listing of Contracting States that have adopted
Article 22(1)
as amended is maintained at WIPO’s website at
www.wipo.int/pct/en/texts/ time_limits.html
. At the time of
publication of this Chapter, only two countries have not adopted
Article 22(1)
as amended: Luxembourg (LU) and the United Republic of Tanzania (TZ). It is noted
that Luxembourg is included in the regional designation “EPO” and that the United
Republic of Tanzania is included in the regional designation “ARIPO.” For those two
remaining Contracting States that have not adopted
Article 22(1)
as amended, if no “Demand” for international preliminary examination has been filed
within 19 months of the priority date, the applicant may be required to complete the
requirements for entering the national stage within 20 months from the priority date
of the international application in the national offices of those states. When
entering the national stage following Chapter I or Chapter II, the applicant has the
right to amend the application within the time limit set forth in
PCT Rule 52.1
or
PCT Rule
78.1
, respectively. After this time limit has expired
(
PCT Article
28
or
PCT Article 41
and
PCT Rule
52
or
PCT Rule 78
), each
designated/elected Office will make its own determination as to the patentability of
the application based upon its own specific national or regional laws
(
PCT Article
27(5)
).
If the applicant desires to obtain the benefit of delaying the
entry into the national stage until 30 months from the priority date in one or more
countries where the 30 month time limit set forth in
PCT Article
22(1)
as amended does not apply, a Demand for international
preliminary examination must be filed with an appropriate International Preliminary
Examining Authority (IPEA) within 19 months of the priority date
ires to obtain the benefit of delaying the
entry into the national stage until 30 months from the priority date in one or more
countries where the 30 month time limit set forth in
PCT Article
22(1)
as amended does not apply, a Demand for international
preliminary examination must be filed with an appropriate International Preliminary
Examining Authority (IPEA) within 19 months of the priority date.
Those states in which the Chapter II procedure is
desired must be “elected” in the Demand.
PCT Rule
54bis.1
requires the Demand to be made
prior to the expiration of whichever of the following periods expires later:
(A) three months from the date of transmittal to
the applicant of the international search report or of the declaration
referred to in
PCT Article 17(2)(a)
,
and of the written opinion under
PCT Rule
43bis.1
; or
(B) 22 months from the priority date.
However, applicant may desire to file the Demand by 19
months from the priority date to extend the national stage entry deadline in
Luxembourg and the United Republic of Tanzania.
The original Demand is forwarded to the International Bureau by the
IPEA. The International Bureau then notifies the various elected Offices that the
applicant has entered Chapter II and sends a copy of any amendments filed under
PCT Article
19
and any statement explaining the amendments and the basis
for the amendments to the IPEA. See
PCT Rule 62
. The International
Bureau also sends the IPEA a copy of the written opinion established by the
International Searching Authority (ISA) unless the ISA is also acting as the IPEA.
See
PCT Rule
62.1(i)
.
VI
cant has entered Chapter II and sends a copy of any amendments filed under
PCT Article
19
and any statement explaining the amendments and the basis
for the amendments to the IPEA. See
PCT Rule 62
. The International
Bureau also sends the IPEA a copy of the written opinion established by the
International Searching Authority (ISA) unless the ISA is also acting as the IPEA.
See
PCT Rule
62.1(i)
.
VI.
INTERNATIONAL PRELIMINARY EXAMINING AUTHORITY (IPEA)
The International Preliminary Examining Authority (IPEA) normally
starts the examination process when it is in possession of:
(A) the Demand;
(B) the amount due;
(C) a translation, if the applicant is required to furnish a
translation under
PCT Rule 55.2
;
(D) either the international search report or a notice of the
declaration by the International Searching Authority (ISA) that no
international search report will be established; and
(E) the written opinion established under
PCT Rule
43bis.1
.
The IPEA shall start the international preliminary examination upon
receipt of the above materials unless the applicant expressly requests to postpone
the start of the international preliminary examination until the expiration of the
later of three months from the transmittal of the international search report (or
declaration that no international search report will be established) and written
opinion; or the expiration of 22 months from the priority date, with the exception
of the situations provided for in
PCT Rule 69.1(b) - (e)
.
The written opinion of the ISA is usually considered the first
written opinion of the IPEA unless the IPEA has notified the International Bureau
that written opinions established by specified International Searching Authorities
shall not be considered a written opinion for this purpose. See
PCT Rule
66.1bis
. Also, the IPEA may, at its
discretion, issue further written opinions provided sufficient time is available.
See
PCT Rule
66.4
lly considered the first
written opinion of the IPEA unless the IPEA has notified the International Bureau
that written opinions established by specified International Searching Authorities
shall not be considered a written opinion for this purpose. See
PCT Rule
66.1bis
. Also, the IPEA may, at its
discretion, issue further written opinions provided sufficient time is available.
See
PCT Rule
66.4
.
The IPEA establishes the international preliminary examination
report (entitled “international preliminary report on patentability”), which
presents the examiner’s final position as to whether each claim is “novel,” involves
“inventive step,” and is “industrially applicable” by 28 months from the priority
date. A copy of the international preliminary examination report is sent to the
applicant and to the International Bureau. The International Bureau then
communicates a copy of the international preliminary examination report to each
elected Office.
The applicant must complete the requirements for entering the
national stage by the expiration of 30 months from the priority date to avoid any
question of withdrawal of the application as to that elected Office; however, some
elected Offices provide a longer period to complete the requirements.
A listing of all national and regional offices, and the
corresponding time limits for entering the national stage after PCT Chapter I and
PCT Chapter II, may be found on WIPO’s website at:
www.wipo.int/pct/en/texts/time_limits.html
.
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## Nearby sections

- [MPEP § 1801 Basic Patent Cooperation Treaty (PCT) Principles](https://www.frixlaw.com/law-library/statutes/MPEP_S1801.md)
- [MPEP § 1802 PCT Definitions](https://www.frixlaw.com/law-library/statutes/MPEP_S1802.md)
- [MPEP § 1803 Reservations Under the PCT Taken by, and Notifications of Incompatibility Made by, the United States of America](https://www.frixlaw.com/law-library/statutes/MPEP_S1803.md)
- [MPEP § 1804 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S1804.md)
- [MPEP § 1805 Where To File an International Application](https://www.frixlaw.com/law-library/statutes/MPEP_S1805.md)
- [MPEP § 1806 Applicants and Inventors](https://www.frixlaw.com/law-library/statutes/MPEP_S1806.md)
- [MPEP § 1807 Agent or Common Representative and General Power of Attorney](https://www.frixlaw.com/law-library/statutes/MPEP_S1807.md)
- [MPEP § 1808 Change in or Revocation of the Appointment of an Agent or a Common Representative](https://www.frixlaw.com/law-library/statutes/MPEP_S1808.md)
- [MPEP § 1809 Access to the USPTO patent electronic filing system](https://www.frixlaw.com/law-library/statutes/MPEP_S1809.md)
- [MPEP § 1810 Filing Date Requirements](https://www.frixlaw.com/law-library/statutes/MPEP_S1810.md)
- [MPEP § 1811 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S1811.md)
- [MPEP § 1812 Elements of the International Application](https://www.frixlaw.com/law-library/statutes/MPEP_S1812.md)
- [MPEP § 1817 PCT Member States](https://www.frixlaw.com/law-library/statutes/MPEP_S1817.md)
- [MPEP § 1818 [Reserved]](https://www.frixlaw.com/law-library/statutes/MPEP_S1818.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/MPEP_S1801. Check the current official text before relying on it. Not legal advice.