Age of an unknown person can be assessed by correlating the physical, skeletal and dental maturity of an individual. The teeth development stage is considered a simple and a reliable method for age estimation. This study was done to estimate age by the development of third molar teeth in Upper Egypt population sample using 10 stages scoring system. It was found that there were strong positive associations between chronological age (CA) and dental age (DA) in males and females in all developmental stages. Males showed significant decrease of mean age than females in developmental stages (7-10). The highest correlation coefficient was found between lower right (LR) and lower left (LL) third molars in males. In females highest correlation was found between upper right (UR) and upper left (UL) third molars. There was statistical significant difference between age group less than 18 years and age groups more or equal to 18 years in all studied parameters for male, female. The most significant predictors of age were upper left (UL) and lower right (LR) third molars measurements for all studied subjects. Conclusions: These finding support the principal role for the use of developmental stage of third molar teeth for prediction of age in Upper Egypt individuals.