Astuce :
| nom commune | pop. | code insee | code siren | code postal |
|---|---|---|---|---|
| Aspret-Sarrat | 128 | 31021 | 213100217 | 31800 |
| Ausson | 592 | 31031 | 213100316 | 31210 |
| Balesta | 158 | 31043 | 213100431 | 31580 |
| Blajan | 433 | 31070 | 213100704 | 31350 |
| Bordes-de-Rivière | 460 | 31076 | 213100761 | 31210 |
| Boudrac | 149 | 31078 | 213100787 | 31580 |
| Boulogne-sur-Gesse | 1658 | 31080 | 213100803 | 31350 |
| Cardeilhac | 258 | 31108 | 213101082 | 31350 |
| Castéra-Vignoles | 59 | 31121 | 213101215 | 31350 |
| Cazaril-Tambourès | 85 | 31130 | 213101306 | 31580 |
| Charlas | 253 | 31138 | 213101389 | 31350 |
| Ciadoux | 226 | 31141 | 213101413 | 31350 |
| Clarac | 676 | 31147 | 213101470 | 31210 |
| Cuguron | 164 | 31158 | 213101587 | 31210 |
| le Cuing | 479 | 31159 | 213101595 | 31210 |
| Escanecrabe | 211 | 31170 | 213101702 | 31350 |
| Estancarbon | 615 | 31175 | 213101751 | 31800 |
| Franquevielle | 328 | 31197 | 213101975 | 31210 |
| Gensac-de-Boulogne | 97 | 31218 | 213102189 | 31350 |
| Labarthe-Inard | 872 | 31246 | 213102460 | 31800 |
| Labarthe-Rivière | 1287 | 31247 | 213102478 | 31800 |
| Lalouret-Laffiteau | 137 | 31268 | 213102684 | 31800 |
| Landorthe | 1028 | 31270 | 213102700 | 31800 |
| Larcan | 180 | 31274 | 213102742 | 31800 |
| Larroque | 292 | 31276 | 213102767 | 31580 |
| Lécussan | 260 | 31289 | 213102890 | 31580 |
| Lespiteau | 79 | 31294 | 213102940 | 31160 |
| Lespugue | 79 | 31295 | 213102957 | 31350 |
| Lieoux | 126 | 31300 | 200014512 | 31800 |
| Lodes | 303 | 31302 | 213103021 | 31800 |
| Loudet | 194 | 31305 | 213103054 | 31580 |
| Miramont-de-Comminges | 743 | 31344 | 213103443 | 31800 |
| Mondilhan | 81 | 31350 | 213103500 | 31350 |
| Montgaillard-sur-Save | 67 | 31378 | 213103781 | 31350 |
| Montmaurin | 192 | 31385 | 213103856 | 31350 |
| Montréjeau | 2676 | 31390 | 213103906 | 31210 |
| Nénigan | 50 | 31397 | 213103971 | 31350 |
| Nizan-Gesse | 100 | 31398 | 213103989 | 31350 |
| Péguilhan | 255 | 31412 | 200064210 | 31350 |
| Pointis-Inard | 920 | 31427 | 213104276 | 31800 |
| Ponlat-Taillebourg | 622 | 31430 | 213104300 | 31210 |
| Régades | 131 | 31449 | 213104490 | 31800 |
| Rieucazé | 55 | 31452 | 213104524 | 31800 |
| Saint-Ferréol-de-Comminges | 60 | 31479 | 213104797 | 31350 |
| Saint-Gaudens (chef lieu) | 11869 | 31483 | 213104839 | 31800 |
| Saint-Ignan | 222 | 31487 | 213104870 | 31800 |
| Saint-Lary-Boujean | 127 | 31493 | 213104938 | 31350 |
| Saint-Loup-en-Comminges | 38 | 31498 | 213104987 | 31350 |
| Saint-Marcet | 370 | 31502 | 213105026 | 31800 |
| Saint-Pé-Delbosc | 144 | 31510 | 213105109 | 31350 |
| Saint-Plancard | 395 | 31513 | 213105133 | 31580 |
| Saman | 145 | 31528 | 213105281 | 31350 |
| Sarrecave | 72 | 31531 | 213105315 | 31350 |
| Sarremezan | 90 | 31532 | 213105323 | 31350 |
| Saux-et-Pomarède | 241 | 31536 | 213105364 | 31800 |
| Savarthès | 195 | 31537 | 213105372 | 31800 |
| Sédeilhac | 65 | 31539 | 213105398 | 31580 |
| les Tourreilles | 380 | 31556 | 213105562 | 31210 |
| Valentine | 875 | 31565 | 213105653 | 31800 |
| Villeneuve-de-Rivière | 1732 | 31585 | 213105851 | 31800 |
| Villeneuve-Lécussan | 570 | 31586 | 213105869 | 31580 |
Le canton de Saint-Gaudens est composé de 61 communes entières pour une population de 35348 habitants.