sex identification of human skeleton is essential for bioarcheological and forensic studies. Determination of Sex is important to establish personal identity. Sex identification accurately depends on the presence of complete remains. Aim: This study aimed to estimate sex from measurements of sacrum and coccyx by computed tomography (CT) of Libyan population. Subjects and methods: A cross-sectional study was carried out in Radiological center of Aljala Hospital of Benghazi and Benghazi Medical Center, Libya on 120 subjects who were divided into 60 males and 60 females. Sex was determined through measuring anterior and posterior sacral lengths (ASL and PSL), anterior and posterior sacrococcygeal lengths (ASCL and PSCL), anterior sacral width (ASW), curved length of sacrum (CLS), length of auricular surface (LAS), mid-sagittal and maximum transverse diameters of base (MDB and MTDB) by using sacrum and coccyx CT. Results: There was very high statistical significant difference between the mean values of different studied parameters between males and females .All these parameters were higher in males except MTDB that was higher in females. Regarding ASW, there was no significant difference between the mean values of males and that of females. The most accurate sex parameters were CLS 99.0%, PSCL 98.3% and MDB 90.5%. Conclusion: Males were significantly higher than females regarding mean values of all studied parameters except MTDB that was higher in females. The most sexually dimorphic individual measurements for sex determination found in the study were CLS, PSCL and MDB. Recommendation: Other studies using different bones and techniques should be done. Keywords: Sacrum, Coccyx, CT, ASL, PSL.