At the applicant's request and on payment of the prescribed fee European patent applications (direct or Euro-PCT) and thus patents can be extended to States for which an Extension Agreement with the EPO has become effective (Extension States).

Extension may be requested for the following States:

The EPO's extension agreements with the Republic of Slovenia (entry into force: 1 March 1994), the Republic of Romania (15 October 1996) and the Republic of Lithuania (5 July 1994) terminated when these three countries acceded to the EPC with effect from 1 December 2002, 1 March 2003 and 1 December 2004 respectively. However, the extension system continues to apply to all European and international applications filed prior to those dates, and to all European patents granted in respect of such applications.

A request for extension to the above-mentioned States is deemed to be made with any European application filed after entry into force and before the termination of respective Extension Agreements. This applies also to Euro-PCT applications provided that the EPO has been designated for a European patent and the Extension State has been designated for a national patent in the international application. The request is deemed withdrawn if the extension fee is not paid within the prescribed time limit (see III, 13.2). It is by paying the extension fee that the applicant decides to extend his application to a certain Extension State. The declaration in Section 34 of the Request for Grant form (Form 1001) or Section 11 of Form 1200 for entry into the European phase before the EPO, where the applicant is asked to state whether he intends to pay the extension fee, is merely for information purposes and intended to assist in recording fee payments.

A request for extension in respect of a divisional application (see IV, 1) is deemed to be made only if the respective request is still effective in the parent application when the divisional application is filed.