Introduction: Evan__ampersandsignrsquo;s Index is one such ventriculography index, which is useful in a wide range of clinical conditions. Develop ment of baseline reference data is necessary when such data is unavailable. Objectives: Evan__ampersandsignrsquo;s Index is useful in various clinical conditions This study aimed to establish reference values for Evans index in the Saudi healthy population. Methods: We retrospectively evaluated 150 computed tomography (CT) scans, 100 were normal, and 50 were having hydro cephalous. Evan__ampersandsign#39;s index (EI) ratio was obtained by measuring the maximum frontal horn width to the maximum transverse diameter of the inner table in the same section on a computer monitor using a meter rule. Results: All scans were age and gender-matched. There is no statistical significance in EI values between males and females in both adult and children groups (p__ampersandsigngt;0.05). The mean EI value ranged from 0.23 to 0.28. We found an apparent increase in EI values with increasing age. However, it was not statistically significant (p__ampersandsigngt;0.05). Conclusion: Our data will be useful in a variety of clinical situations.