Objectives: To investigate the origin, course, relations, tributaries and terminations of azygos system of veins in human cadavers. Methods: A total number of 100 specimens (Foetuses: 10, Children: 8, Adults: 82) were selected for this study. Results: The azygos vein is formed by the union of ascending lumbar vein and subcostal veins in 88% of subjects and subcostal veins alone in 12% of subjects. The termination of azygos vein took place at the level of 4 th thoracic vertebra in 85%, 3rd thoracic vertebra in 8% and 5th thoracic vertebra in 7% of subjects. Conclusions: The anomalies of azygos vein, hemiazygos, and accessory azygos veins are very rare. The variations in the azygos system of veins are utmost importance for thoracic surgeons because vulnerability of damage during surgical procedure.