This research work is a comprehensive account of the emergence and proliferation of Vaishnavism in socio-religious context as well as its forms and practices that evident in the archaeological remains, literary and other sources of Pre-Sankaradeva Assam. The ideology of Vaishnavism was proliferated significantly in the land of Pre-Sankaradeva Assam. Taking a cue from the recent developments in the historiography, the present work is an attempt to trace the Vaishnavism in Pre-Sankaradeva Assam, its forms and practices and its impact on society and culture of the Brahmaputra valley till the 16th century AD.