Background: Adrenal glands are vital part of endocrine system but very little has been described in literature about normalcy of the glands. CT (computerized tomography) is a very good modality to describe the morphology of the glands. Many conditions can be diagnosed by knowing the radiological anatomy of the glands. The objectives is to assess the normal adrenal gland thickness in adult population and to evaluate the relationship of thickness with age and gender. Materials and Methods: It is a hospital based cross-sectional study for a period of 1 year in which the adult patients who underwent CT angiogram of the upper abdomen for clinical indications other than adrenals were included. 1000 scans were included in the study. The maximum thickness of the body, the medial and the lateral limbs were measured at right angles to their long axis, in both adrenal glands. Results: The mean age of the study participants was 54 ± 7.5 years and total of 700 males and 300 females were included. Mean maximum thickness of the right adrenal gland body, medial limb, and lateral limb were 7.16 ± 1.67mm, 4.23 ± 1.45mm and 4.45 ± 1.19mm respectively. The difference in all the measurements of the right and left sides in which, left being larger than the right was statistically significant (P < 0.001). The differences between the measurements among males and females were statistically significant. There was positive correlation between the patient age and all the adrenal gland measurements. Conclusion: We recommend the use of our data as a useful baseline reference range for the Indian adult population, and a guide for radiologists who can use this in their routine cross-sectional reporting practice when they encounter a doubtful “bulky” or “diffuse smoothly enlarged” adrenal gland.