Bismillah Khan was born Qamruddin at Bhirung Raut Ki Gali in Dumraon, about 15 km from Buxar town.
According to the local people, Bismillah Khan's ancestors were court musicians and used to play in Naqqar khana in the princely state of Dumraon.
His father was a shehnai player in the court of Maharaja Keshav Prasad Singh of Dumraon.
When he was barely six or seven, Bismillah moved to his maternal grandfather's home in Varanasi. His uncle, Ali Baksh 'Vilayatu', a shehnai player attached to Varanasi's Kashi Vishwanath Temple, was his guru.