Sheets of Cook Islands, 1990
| Issuer | Date | Desc | State | ||
| - |  |
Cook Islands | 2/19/1990 | empty sheet (#19233) | incomplete |
| - |  |
Cook Islands | 5/2/1990 | empty sheet (#19234) | incomplete |
| - |  |
Cook Islands | 7/20/1990 | empty sheet (#19235) | incomplete |
| - |  |
Cook Islands | 11/29/1990 | Christmas 1990, sheet of 1 type | all added |
| - | no image | Cook Islands | 12/5/1990 | empty sheet (#75752) | incomplete |
| - | no image | Cook Islands | 12/5/1990 | empty sheet (#75753) | incomplete |
| - | no image | Cook Islands | 12/5/1990 | empty sheet (#75754) | incomplete |
| - | no image | Cook Islands | 12/5/1990 | empty sheet (#75755) | incomplete |