Artikel 4

1. Membership of the Union shall be open to all the founding countries and territories of the Union as well as all Caribbean countries and territories.
2. Each of these countries or territories may announce its accession to this Convention at any time by notifying the Secretary General of the Union. They shall sign and ratify the Convention at the earliest opportunity thereafter.
3. Any other country may become a party to the Union by application in accordance with paragraph 4 of this Article, subject however to such terms and conditions as the Conference may determine.
4. Applications for admission to membership of the Union shall be sent to the Secretary General of the Union, accompanied by a formal declaration of intention to accept the obligations of this Convention.
5. The Secretary General of the Union shall consult all members as soon as possible on applications for admission that he has received. A country shall be admitted to membership of the Union if its application for admission has been approved by two-thirds of the members of the Union. The admission shall then be notified to the members of the Union by the Secretariat of the Union and shall take effect on a date agreed between the new member and the Secretary General.