Chapter 4, International Phase of the PCT Applicant's Guide


4.001.   Use of the PCT saves effort – time, work – for any person or firm (“the applicant”) seeking protection for an invention in a number of countries.

4.002.   Use of the PCT also helps the applicant to make decisions about the prosecution of the application before the various national Patent Offices in the national phase of processing.

4.003.   The saving arises primarily from the fact that, under the PCT, the applicant files one application – the international application – in one place, in one language and pays one initial set of fees, and that this international application has the effect of a national or regional application, which, without the PCT, he would have to file separately for each country or region.

4.004.   The help to the applicant in the national phase prosecution of the application follows from the “advice” he obtains from the international search report, a report which is established for each international application, according to high, internationally regulated standards, by one of the Patent Offices that are highly experienced in examining patent applications and that have been specially appointed to carry out international searches.  Those Offices are listed in Annex D (“International Searching Authorities”).  Detailed advice may also be obtained from a written opinion established by the International Searching Authority which gives a preliminary non-binding opinion on whether the claimed invention appears to be novel, to involve inventive step and to be industrially applicable.

4.005. If the applicant so requests (see Form PCT/IB/375), a supplementary international search may be carried out, by one or more of the participating International Searching Authorities (see Annex SISA) other than the one which carried out the main international search. The supplementary international search report(s) (see Form PCT/SISA/501), thus obtained will provide the applicant with a more comprehensive overview of the relevant prior art and enable him to better assess his chances of obtaining patent protection for his invention (see Chapter 8).

4.006.   If the applicant files a demand under Chapter II, international preliminary examination is carried out on the basis of the international search report and the written opinion of the International Searching Authority, and concludes with the international preliminary report on patentability (Chapter II of the PCT). Offices qualified to prepare such reports are specifically appointed to carry out international preliminary examinations and are listed in Annex E (“International Preliminary Examining Authorities”).  Note that those Offices listed in Annex E are the same as those Offices listed in Annex D (“International Searching Authorities”) since, in order to be appointed International Searching Authority, an Office must also hold an appointment as International Preliminary Examining Authority, and vice versa.  The additional benefit for applicants of filing a demand for international preliminary examination is that it provides the applicant with an opportunity to enter into a dialogue with the examiner at the International Preliminary Examining Authority and to possibly amend the international application in order to influence the content of the international preliminary report on patentability (Chapter II of the PCT).

4.007.   The advantages offered by the PCT are given in more detail below.

4.008.   By the single act of filing an international application under the PCT, it is possible to secure the very effect that, without the PCT, would require as many filings of separate applications as there are countries or regions in which the applicant seeks protection.

4.009.   The filing of an international application takes place in one of the languages accepted by the Office with which the application is filed;  for many applicants that will be the language, or one of the languages, used by the national or regional Patent Office of, or acting for, their country.

4.010.   The international application is filed in a single place;  it is generally filed at the national Patent Office of the applicant’s country or at a regional Patent Office acting for the applicant’s country, or it may be filed direct with the International Bureau in its capacity as a receiving Office under the PCT.

4.011.   There is a prescribed form for the international application.  This form must be accepted by all designated Offices for the purposes of the national phase, so that there is no need to comply with a great variety of widely differing formal requirements in the many countries in which protection may be sought.

4.012.   The international fees payable in respect of the filing of an international application may be paid at one time, at one Office and in one currency.  The costs and possible complications connected with the payment, on filing, of many fees in many countries, and generally in different currencies, are thus avoided.

4.013.   Before the applicant goes to the effort and expense of having translations prepared, paying the national or regional fees and appointing agents in the various countries, his views are able to mature to a greater extent than would be possible without the PCT, not only because he has more time, but also because the international search report, the written opinion of the International Searching Authority, the supplementary international search report(s), and the international preliminary report on patentability (Chapter II of the PCT) constitute a solid basis on which he can judge his chances of obtaining protection.  Furthermore, any patents subsequently granted by the designated or elected Offices can be relied on by the applicant to a greater extent than would have been the case without the benefit of the international search report, the written opinion of the International Searching Authority, the supplementary international search report(s), and the international preliminary report on patentability (Chapter II of the PCT).  Moreover, because of the longer time the applicant has for making decisions, he is better placed to assess the technical value and economic interest of patent protection and to select the particular countries in which he desires to continue seeking protection for his invention.  As a result, substantial savings can be made in both translation and filing costs for those countries which are no longer of interest to the applicant.

4.014.   If an international application is filed in a language which is not both a language accepted by the International Searching Authority which is to carry out the international search and a language of publication, it needs to be translated into an appropriate language shortly after filing, but all the translations required by the Offices of or acting for the countries in which the applicant ultimately wishes to obtain protection need to be prepared only much later.  Instead of having to be filed within the 12-month priority period, they are generally not required until the expiration of the time limit referred to in paragraph 4.016.

4.015.   Fees payable to national or regional Patent Offices similarly become due later than they do without the PCT, and only in the case where the applicant decides to go ahead with the processing of his international application at the national or regional Patent Office.  Generally, such national or regional fees must be paid within the same time limit as referred to in paragraph 4.016.

4.016.   Since 1 April 2002, the applicable time limit for entering the national phase is 30 months from the priority date (or even later in some cases) for all Offices except those in respect of which the former 20-month time limit remains applicable unless the applicant files a demand for international preliminary examination before the expiration of 19 months from the priority date, in which case the 30-month time limit (or even later in some cases) will also apply. For regular updates on these applicable time limits, refer to the Official Notices (PCT Gazette), the PCT Newsletter, and the relevant National Chapters; a cumulative table is also available from WIPO’s website at:

4.017.   An international search report (and any supplementary international search report)  which is favorable from the applicant’s viewpoint strengthens his position vis-à-vis the various national or regional Patent Offices, and his arguments for the grant of a patent by those Offices are likely to be more convincing.

4.018.   This is even more true in the case of a favorable international preliminary report on patentability under either Chapter I or II, which contains far more material on which to base an opinion on the chances of obtaining patents than does an international search report.

4.019.   If the international search report and the written opinion of the International Searching Authority are partly favorable and partly unfavorable, the applicant can modify his claims so as to maintain only those which are likely to result in the grant of a patent.  If the international search report and the written opinion are unfavorable, and the applicant consequently decides not to proceed any further, he saves the cost of having the application processed in the various countries. The same applies to supplementary international search report(s).

4.020.   The preceding paragraph also applies in the case of international preliminary reports on patentability under Chapter II of the PCT.

4.021.   Important other advantages resulting from use of the PCT route are referred to in this text.  They consist, among other things, in savings in the procedure before the designated Offices (for instance, there is no need to provide each Office with original drawings, or certified copies of the priority application, there is a reduction in national fees in several countries and the European Patent Office, etc.).


4.022.   Important additional advantages for applicants wishing to protect their inventions in countries party both to any of the various regional patent treaties (see paragraph 2.002) and to the PCT result from combined use of the PCT system and those regional systems.  Not only is the PCT fully compatible with the regional patent systems, but there are possibilities for advantageous combined use of both kinds of system by the applicant, irrespective of the country in which he files.  The following paragraphs deal with the combined use of the PCT with the regional patent systems under which patents may be obtained via the PCT, namely, the ARIPO Harare Protocol, the Eurasian Patent Convention, the European Patent Convention and the OAPI Agreement, via the so-called “ARIPO-PCT route,” “Eurasian-PCT route,” “Euro-PCT route” and “OAPI-PCT route.” In the case of the European Patent Convention, it is also possible to obtain patents through combined use of that Convention and the PCT in the States to which a European patent may be extended or where it may be validated – see paragraph 4.026.

4.023.   Applicants filing a PCT application and wishing to obtain protection in countries party to any of those regional patent treaties obtain, from their PCT application filed, for example, with the Japan Patent Office or with the United States Patent and Trademark Office, the effect of a simultaneous filing with each regional Office concerned for the purposes of obtaining a regional patent.  In such a case, before taking any action outside his country, the applicant can safely wait until the results of the PCT search procedure (and, optionally, of the international preliminary examination) are known and also make full use of the extended period (see paragraph 5.005) by the end of which a translation of the PCT application, if it was not filed in one of the official languages of the regional Office (see the various National Chapters), must be submitted and, where required, an agent appointed for the procedure before that Office.

4.024.   An applicant may file a PCT application with his own national Office as receiving Office, even at the very end of the priority year, and still obtain an immediate automatic filing effect with each of the regional Offices concerned.  A further advantage is that, at the time of filing the PCT application, the applicant pays only one initial set of fees.  The four regional designations which are presently possible cover more than 50 PCT Contracting States.  If, on the other hand, the applicant chooses to file separate regional patent applications on the basis of his first application with his national Office, he will, by the end of the priority year, have to comply with all the requirements of each of the regional treaties as to formalities, fees and appointment of agents.

4.025.   Similar advantages are offered by use of the ARIPO-PCT, Eurasian-PCT, Euro-PCT and OAPI-PCT routes in the reverse direction.  In other words, a national of a State party to one of the regional patent treaties or of one of the States to which a European patent may be extended (see paragraph 4.026) may, instead of filing separate patent applications with his regional Office and, for instance, the Japan Patent Office and the United States Patent and Trademark Office, choose to file, on the basis of a national application or as a first application, an international application under the PCT containing the designation of all PCT Contracting States for the purposes of obtaining, where applicable, both regional and national patents.

4.026.   A further advantage of the Euro-PCT route is the possibility of making use, where available, of the procedure for extension or validation of European patents.  Agreements on extending or validating the protection conferred by European patents have been concluded between the European Patent Organisation and some States which are not party to the European Patent Convention.  Provided that the international application contains a designation for a national patent of the State concerned and also a designation for a European patent the applicant may avail himself of the Euro-PCT route with a view to extending to or validating in that State a European patent subsequently granted on the basis of the international application (see paragraph 5.054 and Annex B (EP), as well as National Chapter Summary (EP)).