25 K/A age determinations on rocks collected on the cross section of the Kali Gandaki are given. The results show that two metamorphisms can be defined in this area: one Precambrian (800-1250 My.); another one Alpine (Himalayan) (15-25 My.) somewhat older than this of the Everest area (10-17.5 My.). The hypothesis of the existence of another metamorphism, although very unlikely, should however not yet be completely eliminated. These age determinations raise some geological problems, too.