The canton Castelginest has 10 communes.
| Code | Name | Population ▼ |
|---|---|---|
| 31116 | Castelginest | 11 271 |
| 31022 | Aucamville | 9 623 |
| 31490 | Saint-Jory | 8 662 |
| 31467 | Saint-Alban | 6 534 |
| 31091 | Bruguières | 6 202 |
| 31182 | Fenouillet | 5 784 |
| 31230 | Gratentour | 4 906 |
| 31293 | Lespinasse | 3 251 |
| 31186 | Fonbeauzard | 3 204 |
| 31205 | Gagnac-sur-Garonne | 3 198 |