| Abruzzo: | 13 | Liguria: | 2 | Sicilia: | 162 |
| Basilicata: | 25 | Lombardia: | 8 | Toscana: | 36 |
| Calabria: | 36 | Marche: | 4 | Umbria: | 4 |
| Campania: | 141 | Molise: | 7 | Veneto: | 4 |
| Emilia Romagna: | 13 | Piemonte: | 5 | ||
| Friuli V. Giulia: | 5 | Puglia: | 337 | ||
| Lazio: | 53 | Sardegna: | 2 |
TOTAL members: 857
* During the general meeting of Terrasini a change to the Statute has been made, under which, Experts in Oncology will be recognized as regular members of the Association although outside the geographical area of NATIONS.
data updated to June 16, 2023