| Issuer | Date | Desc | State | ||
| - | no image | Nicaragua | 4/17/1958 | Brussels Exposition, sheet of 6 types | all added |
| - | no image | Nicaragua | 5/8/1958 | 17th Convention of Lions International of Central America, empty sheet (#28014) | incomplete |
| - | no image | Nicaragua | 5/8/1958 | 17th Convention of Lions International of Central America, empty sheet (#28015) | incomplete |
| - | no image | Nicaragua | 12/15/1958 | Opening of UNESCO Headquarters Building, empty sheet (#28016) | incomplete |
| - | no image | Nicaragua | 12/15/1958 | Opening of UNESCO Headquarters Building, empty sheet (#28017) | incomplete |