21 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. ] :
| | AUSTRIA | (Vienna) | | President Adolf Schaerf | | |
| | BELGIUM | (Brussels) | | King Baudoin I | | |
| | CANADA | (Ottawa) | | Queen Elizabeth II | | |
| | SWITZERLAND | (Berne lq + Lausanne j) | | President Friedrich Traugott Wahlen | | |
| | WEST GERMANY | (Bonn ar + Karlsruhe d) | | Bundespresident Heinrich Luebke | | |
| | DENMARK | (Copenhagen) | | King Frederick IX | | |
| | SPAIN | (Madrid) | | Caudillo Francisco Franco | | |
| | EUROPA | (Brussels o + Luxembourg j + Strasbourg l) | | President Walter Hallstein (de) | | |
| | FRANCE | (Paris) | | President Charles de Gaulle | | |
| | GREECE | (Athens a) | | King Paul I | | |
| | IRELAND | (Dublin) | | President Eamon de Valera | | |
| | ICELAND | (Reykjavik a + Alftanes r) | | President Asgeir Asgeirsson | | |
| | ITALY | (Rome a) | | President Giovanni Gronchi | | |
| | LUXEMBOURG | (Luxembourg a) | | Grand Duchess Charlotte | | |
| | 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 | | |
| | TURKEY | (Ankara a) | | President Cemal Gursel | | |
| | UNITED KINGDOM | (London a + Westminster lr + Edinburgh s + Windsor r) | | Queen Elizabeth II | | |
| | AMERICA | (Washington-District of Columbia) | | President John Fitzgerald Kennedy | | |