| Issuer | Date | Desc | State | ||
| - | no image | Micronesia | 5/3/1990 | Stamp World London 90, sheet of 1 type | all added |
| - | no image | Micronesia | 5/6/1990 | 150th Anniversary of the Penny Black, sheet of 1 type | all added |
| - | no image | Micronesia | 8/10/1990 | Expo 90, sheet of 1 type | all added |
| - | no image | Micronesia | 11/15/1990 | Christmas 1990, sheet of 9 types | all added |