Incisors from 68 known-age moose (Alces alces) were sectioned and the ages of the animals estimated from cementum layers. Mean age determined in this manner overestimated true age by 0.5 yr with errors ranging between -1 and +3 yr. Cross sections were preferred to longitudinal sections. The major error resulted from difficulties in distinguishing discrete cementum layers. Other sources of error were discussed and the annual sequence of cementum deposition described.