Yadav is survived by his wife, a daughter and a son.
A statement from the Fortis Memorial Research Institute said Yadav was brought to the emergency ward in an unconscious and unresponsive state.
"On examination, he did not have any pulse or recordable blood pressure. He underwent CPR as per ACLS protocols. Despite best efforts, he could not be revived and was declared dead at 10.19 pm," the statement said as quoted by news agency PTI.
The information of Yadav's demise has also been confirmed by his daughter through a Facebook post.
Yadav, who was one of the top socialist leaders of the Hindi belt, had started his political career during the anti-emergency movement of the mid 1970s.
In 1974, he was first elected to the Lok Sabha at the age of 27. He registered a victory in by-poll from Madhya Pradesh's Jabalpur seat. He was then elected from Uttar Pradesh's Badaun parliamentary seat in 1989. Further, Yadav was elected from Bihar's Madhepura Lok Sabha constituency in 1991, 1996, 1999, and 2009.
The RJD leader had also served as the Union Minister for Civil Aviation, Consumer Affairs, food and public distribution in the NDA government which was led by Atal Bihari Vajpayee between 1999 and 2004.
He along with incumbent Bihar CM Nitish Kumar was the co-founder of the Janata Dal-United in 2003.
Yadav who had launched his own party Loktantrik Janata Dal, merged with Lalu Yadav's outfit RJD in March 2020 which he said was the "first step towards a united opposition", ANI reported
Sharad Yadav had formed Loktantrik Janata Dal in 2018 and miffed with Janata Dal (United) returning to an alliance with the BJP in Bihar.
(With inputs from agencies)
