On 19 March 2025, Montenegro adopted several patent law amendments to improve the procedure for extending the national patent validity. Effective 27 March 2025, the amendments require patent holders to submit evidence of patentability before the end of the ninth year of validity in order to ensure continued protection beyond the tenth year. Since patents in Montenegro are granted on the basis of formal examination only, holders must provide proof of patentability to maintain their rights.

Under the amended regime, proof of patentability may be provided as part of a search report with a written opinion prepared by intergovernmental or foreign offices under agreements with the Montenegrin IPO. This is now formally recognised as sufficient evidence to maintain patent protection beyond the tenth year.

In April 2025, Montenegro and the European Patent Office (EPO) signed a Working Agreement on Search Cooperation, effective 1 December 2025. The agreement allows the Montenegrin IPO to request the EPO to execute search reports and written opinions on the patentability of national patent applications and patents, providing substantive evidence to support the continued validity of patents beyond the tenth year.

Montenegro is finalising a similar agreement with Croatia. Since Croatian is an official language in Montenegro, search reports from the Croatian IPO can be used without translations. This will eliminate translation costs for patent applications into English and search reports into Montenegrin, easing the financial burdens.

As of 1 August 2025, Montenegro's accession to the London Agreement simplified translation requirements, but applicants seeking validation of European patents in Montenegro must provide Montenegrin translations of claims and drawings, along with the EPO’s B1 document in English. This requirement strengthens procedural clarity and aligns national practice with European standards.