| Country | Action | Action Date | Effective Date |
|---|
| AUSTRIA | Signature | 05/08/1955 | |
| AUSTRIA | Ratification | 30/09/1959 | |
| BELGIUM | Signature | 05/08/1955 | |
| BELGIUM | Ratification | 06/09/1961 | |
| DENMARK | Signature | 05/08/1955 | |
| DENMARK | Ratification | 25/06/1959 | |
| FRANCE | Signature | 05/08/1955 | |
| FRANCE | Ratification | 21/02/1959 | |
| GERMANY FEDERAL REPUBLIC | Signature | 05/08/1955 | |
| GERMANY FEDERAL REPUBLIC | Ratification | 26/08/1959 | |
| GREECE | Signature | 05/08/1955 | |
| ICELAND | Signature | 05/08/1955 | |
| ICELAND | Ratification | 02/03/1962 | |
| IRELAND, REPUBLIC OF | Signature | 05/08/1955 | |
| IRELAND, REPUBLIC OF | Reservation | 05/08/1955 | |
| ITALY | Signature | 05/08/1955 | |
| ITALY | Ratification | 06/12/1961 | |
| LUXEMBOURG | Signature | 05/08/1955 | |
| NETHERLANDS THE | Signature | 05/08/1955 | |
| NETHERLANDS THE | Ratification | 26/11/1957 | |
| NORWAY | Signature | 05/08/1955 | |
| NORWAY | Ratification | 12/01/1959 | |
| PORTUGAL | Signature | 05/08/1955 | |
| PORTUGAL | Ratification | 20/10/1960 | |
| SPAIN | Accession | 20/07/1959 | |
| SWEDEN | Signature | 05/08/1955 | |
| SWEDEN | Ratification | 20/02/1959 | |
| SWITZERLAND | Signature | 05/08/1955 | |
| SWITZERLAND | Ratification | 27/10/1955 | |
| TURKEY | Signature | 05/08/1955 | |
| UNITED KINGDOM | Signature | 05/08/1955 | |
| UNITED KINGDOM | Ratification | 26/07/1960 | |