In India, from the time of emergence of empires in circa 300 BCE till the rise of British power in eighteenth century, military mercenaries and private military companies dominated the politico-military landscape. Premodern India had both secular (military guilds) and religious (based on temples and akharas) military corporations. The mercenaries were mostly marginal peasants and demobilised soldiers. They were hired through the agency of their clan leaders, tribal chieftains or the zamindars (large landlords) in whose villages they resided. Historians argue that the presence of the mercenaries and extra state military corporations prevented the rise of strong states in premodern India. In this paper, based mostly on indigenous sources, I argue that the military mercenaries and the private military corporations of pre-British India were at the forefront of technological development. The mercenaries were the channel through which tools, techniques, and ideas of warfare were transferred. The rulers relied on the mercenaries because of their military skills and in the long run they also proved to be cheaper compared to the cost of maintaining permanently a large regular army.