WO (PCT) publication numbers

The EP Register provides file inspection for all publicly available EP applications, Euro-PCT applications (Entry into the regional phase, Form 1200) and for international applications under the PCT where the EPO has been designated as one of the following:

  • Receiving Office (PCTRO)
  • International Searching Authority (PCTISA)
  • Supplementary International Searching Authority (SISA)
  • International Preliminary Examination Authority (IPEA) (PCT2)


(Article 30 PCT)
(OJ EPO 2003, 382)
(OJ 2018, A14)

Searching with PCT publication numbers

Depending on the year of publication, you can enter three different PCT publication number formats in the Register. The number format has changed over time as follows:

  • From 1978 to 30 June 2002 numbers have the format WOyynnnnn (two digits for the year and five for the serial number)
  • From 1 July 2002 to 31 December 2003 numbers have the format WOyynnnnnn (two digits for the year and six for the serial number)
  • Since 1 January 2004 numbers have the format WOyyyynnnnnn (four digits for the year and six for the serial number)

The format valid from 1 January 2014 onwards is also the standard format and can be used for all PCT publications. It consists of the WIPO code WO (two letters), the year (four digits) and a serial number of six digits: WOyyyynnnnnn.

In the Register, patent document numbers entered in Smart search trigger a search for all types of patent documents, i.e. the Register searches for application, publication and priority numbers, using the search syntax num =. If you want to search for a particular type of patent document number, you can use a corresponding Smart search field identifier. If you only want to search for the publication number, for example, you enter your search using the field identifier pd= followed by the number, e.g. pd = WO2007IB51010. In Advanced search you simply enter the numbers as they appear in the corresponding search fields.

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Smart search field identifiers