The history of mankind is replete with devastating wars since the beginning of civilisation. The Indian history also witnessed many wars. The earliest wars in India appear to have been fought by the people of the Indus Valley civilisation. Their expertise in building forts to defend themselves confirms this theory. Subsequently, the Aryans waged wars against the natives of the land. The battles depicted in the epics of Ramayana and Mahabharata further provide valuable information about the warfare mechanism of the ancient period. Later, Sisunagas, Nandas, Mauryas and Guptas fought various wars to build and consolidate their empires. Findings at the sites of the Indus Valley civilisation like fort-like structures, protective walls and arrow-heads, reveal the war mechanism of those people. Besides wood and stone, their weapons appear to have been made of bronze and copper. The discovery of iron during the Janapadas period accelerated technological changes, and weapons like spears, swords, etc., made out of iron, came into vogue. The ‘Battle of Sindh’ has been considered as the first battle during the ancient Indian history however we are not getting the sufficient sources about this theory. It was fought in between people of the Indus Valley civilisation and the Aryans.