| Country | Action | Action Date | Effective Date |
|---|
| AUSTRIA | Signature | 29/06/1956 | |
| AUSTRIA | Ratification | 17/05/1957 | |
| BELGIUM | Signature | 29/06/1956 | |
| BELGIUM | Ratification | 22/07/1960 | |
| DENMARK | Signature | 29/06/1956 | |
| DENMARK | Ratification | 03/09/1956 | |
| FRANCE | Signature | 29/06/1956 | |
| GERMANY FEDERAL REPUBLIC | Signature | 29/06/1956 | |
| GREECE | Signature | 29/06/1956 | |
| ICELAND | Signature | 29/06/1956 | |
| IRELAND, REPUBLIC OF | Signature | 29/06/1956 | |
| IRELAND, REPUBLIC OF | Ratification | 11/01/1957 | |
| ITALY | Signature | 29/06/1956 | |
| ITALY | Ratification | 14/03/1961 | |
| LUXEMBOURG | Signature | 29/06/1956 | |
| NETHERLANDS THE | Signature | 29/06/1956 | |
| NETHERLANDS THE | Ratification | 28/08/1958 | |
| NORWAY | Signature | 29/06/1956 | |
| NORWAY | Ratification | 08/03/1957 | |
| PORTUGAL | Signature | 29/06/1956 | |
| SWEDEN | Signature | 29/06/1956 | |
| SWEDEN | Ratification | 18/02/1957 | |
| SWITZERLAND | Signature | 29/06/1956 | |
| SWITZERLAND | Ratification | 29/06/1956 | |
| TURKEY | Signature | 29/06/1956 | |
| UNITED KINGDOM | Signature | 29/06/1956 | |
| UNITED KINGDOM | Ratification | 23/05/1958 | |