23 Members (excluding the associate or suspended members but including the countries represented on their behalf) [The rulers are not necessarily the representatives in the organisation. ] :
| | NETHERLANDS ANTILLES | (Willemstad) | | Queen Juliana | | |
| | ARGENTINE | (Buenos Aires a + Olivos r) | | President Arturo Frondizi | | |
| | BELGIUM | (Brussels) | | King Baudoin I | | |
| | BULGARIA | (Sofia) | | Todor Zhivkov | | |
| | BRAZIL | (Rio de Janeiro a + Brasilia f) | | President Juscelino Kubitschek | | |
| | CANADA | (Ottawa) | | Queen Elizabeth II | | |
| | SWITZERLAND | (Berne lq + Lausanne j) | | President Paul Chaudet | | |
| | WEST GERMANY | (Bonn ar + Karlsruhe d) | | Bundespresident Theodor Heuss | | |
| | DENMARK | (Copenhagen) | | King Frederick IX | | |
| | SPAIN | (Madrid) | | Caudillo Francisco Franco | | |
| | FINLAND | (Helsinki a + Kultaranta s) | | President Urho Kekkonen | | |
| | FRANCE | (Paris) | | President Charles de Gaulle | | |
| | GREECE | (Athens a) | | King Paul I | | |
| | GUATEMALA | (Guatemala City) | | President Miguel Ydigoras Fuentes | | |
| | ITALY | (Rome a) | | President Giovanni Gronchi | | |
| | JAPAN | (Tokyo) | | Emperor Hirohito | | |
| | MOROCCO | (Rabat a + Tangier s) | | King Muhammad V | | |
| | NETHERLANDS | (Amsterdam a + The Hague jlr + Wassenaar r) | | Queen Juliana | | |
| | NORWAY | (Oslo) | | King Olav V | | |
| | PORTUGAL | (Lisbon) | | President Americo Thomaz | | |
| | SWEDEN | (Stockholm) | | King Gustav VI Adolphe | | |
| | UNITED KINGDOM | (London a + Westminster lr + Edinburgh s + Windsor r) | | Queen Elizabeth II | | |
| | AMERICA | (Washington-District of Columbia) | | President Dwight David Eisenhower | | |