The Patent Cooperation Treaty

An inventor can file a single “international application” with the PCT that establishes a filing date for all member countries.

The  Patent Cooperation Treaty  (PCT) is administered by the World Intellectual Property Organization in Geneva. Under the Patent Cooperation Treaty (PCT), the inventor can file a patent application in the U.S. and then file a single “international application” (the “PCT application”) with the PCT Department of the USPTO that establishes a filing date for all member countries. This filing does not result in a universal PCT patent; the inventor must eventually file separate or “national” applications in each PCT jurisdiction. However, the PCT application provides the following advantages:

  • By filing one PCT application, the inventor obtains a filing date that is good in every member country in which the inventor seeks patent protection.
  • An initial international patent search will be conducted by the USPTO or the European patent Office (EPO) (the inventor makes the designation) on the PCT application and member countries will rely heavily on this search. This saves a great deal of expense and delay that would result if separate searches were conducted in each country.
  • The inventor may designate to have the examination performed in the USPTO or EPO depending on whether the applicant elects a process known as “Chapter II” within 22 months from the U.S. filing date or three months from transmittal of the search report.

The PCT Process

If the inventor desires patent coverage in a PCT country, the PCT application must be translated for non-English-speaking jurisdictions. It also must be filed in the foreign country within 30 months after the inventor’s U.S. filing date.  After filing the PCT application, the inventor will receive a “search report” from either the USPTO or EPO depending on which is elected by the applicant. The inventor can then amend the claims once and submit a brief statement responding to any issues raised by the report. The inventor eventually receives a formal indication of allowability (or rejection) from the examiner.

Before 30 months (whether or not the application is allowed or rejected), the inventor can file the application in any PCT jurisdiction. Each of the separate countries and the EPO will rely to a great extent on the international examination they will receive from the PCT’s International Bureau. All PCT members are members of the Paris Convention, but not vice versa.

For additional assistance filing a PCT application, consult Patent It Yourself, by attorney David Pressman (Nolo), or review The PCT Applicant’s Guide from the PCT Department of the USPTO or the PCT section of the USPTO’s website. Information regarding a country’s patent laws may be obtained from the country’s consulate office in the U.S.

Preparing an International Application Under the PCT

To file a PCT application, the inventor prepares the original U.S. application and drawings on A4 size paper. The main differences between the PCT and U.S. national formats (both of which are acceptable for U.S. applications) are the drawing size and margins, location of page numbers, and spacing between typed lines.

In addition to the PCT application, a “Request” form (USPTO PCT/RO/101) and a “transmittal letter” (Form USPTO 1382) are required. Both forms are available from the USPTO website, The World Intellectual Property Organization (WIPO) has software (“PCT-Easy”) that enables an applicant to pay reduced fees and automate the process of completing PCT filing forms. Check out the WIPO's PCT documentation (

It is advisable to file the PCT application at least a month before the anniversary of the inventor’s U.S. filing date. However, the inventor can mail the PCT application as late as the last day of the one-year period from the inventor’s U.S. filing date if the inventor uses Express Mail and completes the Express Mail Certification on page 1 of the transmittal letter.

The inventor will receive a filing receipt and separate serial number for the international PCT application. The application will eventually be transmitted for filing to the countries (including the EPO) designated on the inventor’s request form. If the inventor makes any minor errors in the PCT application, the PCT Department of the USPTO will give the inventor a month to correct them. When the inventor receives the PCT search report (either from the USPTO or EPO), the inventor can comment on it and amend the inventor’s claims once if desired, but no extended prosecution or negotiation is permitted.

Chapter II of the PCT

Within 22 months from the U.S. filing date or three months from transmittal of the search report, the inventor can elect Chapter II. This requires selecting either the USPTO or the EPO to examine the application. If the inventor selects the EPO to do the examination, the inventor must file the papers with the EPO in Munich and pay the fee in euros. The inventor will receive an examination report indicating which claims will actually be allowed or rejected. The inventor can amend the application once and even interview the inventor’s examiner.

National Filings Under the PCT

Unless Chapter II was elected, the inventor must file a national application in each country or jurisdiction in the inventor’s PCT application within 30 months from the inventor’s U.S. filing date. (If Chapter II was elected, the applicant must file applications in non-EPO countries and the EPO by 20 months from the U.S. filing date.) As mentioned, each of the separate countries and the EPO will rely to a great extent on the international examination received as part of the PCT process. In most cases this examination will be based upon the EPO patent search or adopted from the U.S. patent search. This is one advantage of the PCT approach because the inventor saves money and time by not having to separately and fully prosecute an application in each country in which the inventor elected to file.

Portions of this article are derived from  Nolo's Patents for Beginners.


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