Sudras were belonged to the Aryan stock and were a section of Aryan community. The varna sytem developed under priestly influence. It is evident that the Sudras appear as a social class only towards the end of Early vedic period when the Purusasukta version of their origin inserted in to the tenth book of the Rig-Veda. One would like to know why the fourth varna come to be called as Sudras. It appears that the word Sudra was derived from the Sanskrit word Dasa. It seems that the word Sudra derived from a conquered tribe of that name as Sudra existed as a tribe in the fourth century B.C. The question is whether the Arya and Sudra represent two social classes or two tribal groups. The latter supposition seems to be plausible. The Sudras are repeatedly mentioned as a tribe in the Mahabharata. Contradictory views have been expressed on the ethnological classification of the Sudra tribe whether the Sudras were an Aryan or Pre-Aryan tribe. If Aryan when did they come to India? Formerly it was maintained that the Sudras were an earlier wave of Aryans later it came to be held that they were a stream of the Pre-Aryan people. From the available data it is believed that Sudras tribe had some affinity with the Aryans. Further the Sudras have never been mentioned in the list of the Pre-Aryan people such as Dravidas, Pulindas, Sabaras etc. They were always located in the North-West which was an area mainly occupied by the Aryans. The inscription of Odisha provide as sufficient information regarding the existence of Brahmins, Khatriyas, Vaisyas and Karanas but silent about the sudras and their functions in the society. But the Sudras were incourse of time because of their economic condition occupied the status of Khatriyas.