Objectives: Morphometric and morphological study of the bones play an important role in determination of sex, age and identification of an individual and skull is the second important tool to pelvis in this regard. Mastoid process is a dimorphic bone situated at the basolateral region of the skull and remains least damaged due to its position. This study was an attempt to evaluate the use of mastoid process in the determination of sex. Methodology: This cross sectional study was carried out in the settings of Department of Anatomy and Forensic Medicine at North Karnataka for the period of one year from July 2014 to June 2015. A total of 100 complete undamaged dried skulls of known sex were used for the study, (50 male and 50 female skulls). Length of the mastoid process on both sides was recorded using the Frankfurt__ampersandsignrsquo;s plane. Measurements were taken by using Vernier caliper. Results: The mean mastoid process length among males at right was 30.20 __ampersandsignplusmn; 2.64 mm and at left it was 30.70 __ampersandsignplusmn; 3.09 mm compared to 26.20 __ampersandsignplusmn; 2.57 mm in females at right and 26.20 __ampersandsignplusmn; 3.49 mm at left respectively. The difference observed was statistically significant (p__ampersandsignlt;0.001). Conclusion: The mastoid length in females is significantly less compared to males at right as well as left.