Guide for applicants, Part 2: PCT procedure before the EPO (Euro-PCT Guide)

Where the applicant claims the priority of an earlier application, a certified copy of that earlier application ("the priority document") must be filed with the receiving Office or the International Bureau within 16 months after the priority date. However, if the earlier application was filed with the receiving Office, the applicant may request that the receiving Office transmits a certified copy of the earlier application to the International Bureau. For that purpose a check-box is provided in Box No. VI of the PCT request form. 

If the EPO is requested to prepare and transmit a priority document to the International Bureau a fee is due.  

Please note that the procedure whereby the EPO includes free of charge a copy of the previous application from which priority is claimed in the file of a European patent application does not apply in respect of an international application processed by the EPO as receiving Office (see point 614). Moreover, the obligation to furnish the priority document cannot be met by a request to the IB under the Digital Access Service (DAS) to retrieve that document from an electronic library, because the EPO does not participate in this system.