The development of permanent premolar and molar teeth was examined in mandibular radiographs from wild sika deer (Cervus nippon) of known ages (74 males, 66 females, 4 unknown; age range 1–54 months) from Hyogo Prefecture. Tooth development was scored according to the method described by Brown & Chapman (1991a, b). Stage-specific scores for all molar and premolar teeth were summed, and simple cubic regression analysis was used to analyse the relationship between the total score and age in months. Our analysis showed a strong cubic correlation between the total score and chronological age in months. The equation obtained from this analysis was used to estimate age within a 95% prediction interval in seven archaeological specimens from the Asahi archaeological site in central Japan. Copyright © 2010 John Wiley & Sons, Ltd.