The stages of permanent tooth development observed in radiographs of the mandible are described and analysed for known-aged red deer (Cervus elaphus). The ages by which the different stages of development were reached have been determined. By allocating scores for these different stages, the scores that may be expected for a particular age have been identified. Lastly, the predicted age was given, together with 95% prediction intervals obtained from a regression of age on total molariform scores. Tooth development in red deer was usually completed by 33 months. These data can be used to assess the ages of animals of unknown age.