Sex determination is a crucial issue and is usually the first step in the process of identification in forensic investigations. However, it remains a very challenging task. The aim of this study was to determine the validity of radiographic measurements, from the superior and inferior borders of the mental foramen to the lower border of the mandible (S-L and I-L), and from the medial margin of the mental foramen to the mandibular symphisis (MF -MS) on both right and left sides of the mandible, in sex determination in a sample of Egyptian population. The studied measurements were obtained digitally from high quality panoramic radiographs using imaging software. The recruited sample consisted of four hundred and thirty panoramic radiographs of patients aged 20 to 68 years with equal sex distribution. They were divided into two age groups; group 1 (from 20-50 years) and group 2 (more than 50 years). No significant difference was found in the studied measurements between the right and left sides of the mandible in both sexes. The mean Rt S-L, Rt I-L, and Rt MF-MS were significantly higher in males than females in both age groups. The receiver operating characteristic curve analysis identified the Rt I-L as the best valid and accurate one (area under the curve was 0.950 and accuracy was 87.2%) for sex determination. A combination of Rt S-L, Rt I-L, and Rt MF-MS for sex prediction identified males correctly in 95.3% and females in 94.4% of the studied cases with overall predictive accuracy of 94.9%. It could be concluded that a combination of SL, I-L, and MF-MS has shown promising applications in sex determination among Egyptians. For more population specific standards and accurate sex identification, further research on a greater number of cases including more age groups is recommended.