Age estimation is fundamental in forensic examinations, either in legal conditions that including living people or to identify skeletal remains. The mandible gives better growth than the other facial bones and presents morphological alterations that relate to size and remodeling during human growth. Previous studies have reported the use of facial reconstruction by three dimensional computed tomography (3D CT) for individual identification. The aim of this study was to investigate role of 3D CT in age estimation from mandible of a sample of Libyan Population in Tripoli. This study was conducted in National Cancer Institute, Tripoli, Libya on 200 adults for 6 months (from the beginning of January to the end of June, 2020). All subjects were subjected to 3D-CT scan to assess seven mandibular parameters which were gonial angle, ramus length, minimal ramus breadth, coronoid height, gonion-gnathion length, bicondylar breadth and bigonial length. The results showed significant positive correlation between gonial angle, gonion-gnathion length and age. While, there was significant negative correlation between ramus length, bigonial length and age either in total, male and female samples. By simple linear regression equations, age can be estimated from mandibular parameters proven to be statistically significant with highest R2 (coefficient of determination) were gonial angle and ramus length either in total, male and female samples. Additionally, there were no significant differences between actual age and estimated age by gonial angle and ramus length either in total, male and female samples. It can be concluded that age can be estimated from mandibular metric parameters measured by 3D-CT with high degree of accuracy.