[en] The effects of X radiation on the structure of the parotid glands of young rats are studied by means of morphologic technique. Seventy male rats (Rattus norvegicus, albinus Holtzman) were distributed in two experimental groups: Group 1- irradiated and Group 2- control. The region of the parroted glands was irradiated with a dose of 300 rads from 48 to 48 hours up to an exposition of 1.200 rads. After predetermined periods the animals belonging to both groups were sacrificed and the parotid glands were removed for histopathologic evaluation. The serous acini showed to be radium sensitive and in the periods closer to the radiation, the glandular structure des organization and degeneration was noted. (M.A.C.)