There are 20 municipalities and 5 cities composing Negros Oriental including the famous Dumaguete City. Listed below are the postal codes:
| Location | Zip Code |
| Amlan | 6203 |
| Ayungon | 6210 |
| Bacung | 6216 |
| Bais City | 6206 |
| Basay | 6222 |
| Bayawan City | 6221 |
| Bindoy | 6209 |
| Canlaon City | 6223 |
| Dauin | 6217 |
| Dumaguete City | 6200 |
| Guihulngan | 6214 |
| Jimalalud | 6212 |
| La Libertad | 6213 |
| Mabinay | 6207 |
| Manjuyod | 6208 |
| Pamplona | 6205 |
| San Jose | 6202 |
| Santa Catalina | 6220 |
| Siaton | 6219 |
| Sibulan | 6201 |
| Tanjay City | 6204 |
| Tayasan | 6211 |
| Valencia | 6215 |
| Valle Hermoso | 6224 |
| Zamboanguita | 6218 |