Under Article 91.1, the IP Law of Vietnam, an applicant for registration of an invention may claim priority on the basis of the first application for registration of protection of the subject matter if the following conditions are fully satisfied:
(a) The first application patent was filed in Vietnam or in a country being a contracting party to a treaty of which the Socialist Republic of Vietnam is also a member, containing provisions on priority right, or in a country which has agreed with Vietnam to apply such provisions;
(b) The applicant is a citizen of Vietnam or of a country defined in sub-clause (a) of this clause, who resides or has a production or business establishment in Vietnam or in a country defined in sub-clause (a) of this clause;
(c) The claim for the priority right is clearly stated in the application and a copy of the first application certified by the receiving office is enclosed;
(d) The application is filed within the time-limit provided for in a treaty of which Vietnam is a member.