Aims and objectives: The objectives were to study the morphometry of the foramen magnum on C.T. Scan and to evaluate its anteroposterior diameter, transverse diameter of the foramen magnum. Also to compare the diameter of foramen magnum in males and females. Material and Methods: We examined 100 C.T.Scans of normal persons. The anteroposterior and transverse diameters of foramen magnum were measured with help of computer software and analysis done statistically. We observed for any variations in the shape of foramen magnum. Results: Out of 100 C.T. scans studied, 61 cases were of males in whom the anteroposterior and transverse diameter were observed to be 33.90+2.61 mm __ampersandsignamp; 28.05+2.22 mm respectively. In 39 females, anteroposterior diameter and transverse diameter of foramen magnum were 32.35+3.16 mm, 26.88+2.96 mm respectively. Conclusion: Unpaired t-test shows diameters of foramen magnum were greater in males than in females as p-value less than 0.05 hence it is statistically significant. The data obtained may be of useful to the neurosurgeons in analyzing the morphological anatomy of craniovertebral junction. The findings are also enlightening for the anthropologists, morphologists and clinical anatomists. __ampersandsignnbsp; __ampersandsignnbsp; __ampersandsignnbsp; __ampersandsignnbsp;