A study of the age and sex structure in a selected beaver (Castor canadensis carolinensis) population was conducted from January 1971 to January 1972 in Green County, Georgia. Twenty-four beavers were trapped from four colonies in the study area. The animals were aged by cranial measurements and dental cementum and sexed by necropsy. There was no significant sex ratio difference in the kit and yearling classes. The sex ratio for the 2-year-old and adult classes was 13 males to 7 females. The sex ratio for the total population was 14 males to 10 females. The four study colonies averaged six beavers per colony.