Das, who was admitted to Patna Medical College and Hospital two days back, breathed his last at 4 am.
He is survived by two sons and one daughter. His wife passed away earlier.
Upon learning of Das's death, Bihar Chief Minister Nitish Kumar rushed to his home at Kankarbagh in Patna. Kumar also announced a state funeral for Das.
Das was chief minister of Bihar as the head of the Janata Party government in 1979.
He had defeated Ram Vilas Paswan in the Hajipur (SC) Lok Sabha seat in 2009, but in the parliamentary polls last year, had lost to the latter.
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