He was 90.
Yadav, who served as Madhya Pradesh Governor from 2011-September 2016, breathed his last at Sanjay Gandhi Postgraduate Institute of Medical Sciences here at 9.15 AM, Congress sources said.
Yadav's name had figured in the Vyapam scam, a multi-crore scandal in the Madhya Pradesh Professional Examination Board, which involved several high-profile professionals, politicians and bureaucrats.
The Madhya Pradesh High Court had later quashed the FIR filed against him in connection with the scam, holding that he enjoyed immunity while in office.
Prime Minister Narendra Modi, UP Chief Minister Akhilesh Yadav and Governor Ram Naik expressed grief over the demise of the Congress veteran hailing from Azamgarh.
"The Prime Minister has condoled the passing away of former UP CM & MP Governor, Shri Ram Naresh Yadav," the PMO said in a tweet.
Naik offered condolences and prayed for peace for the departed soul, whereas Akhilesh said, "Ram Nareshji had always worked for the welfare of the poor and deprived and his death is an irreparable loss,".
After completing his tenure in Madhya Pradesh, he had not been keeping well and was undergoing treatment at the PGI, sources said.
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Yadav served as Uttar Pradesh Chief Minister from 1977 to 1979 and inducted Mulayam Singh Yadav as Cooperative Minister in his Janata Party Government, giving a boost to the fledgling political career of the young socialist leader.
Though a UPA 2 appointee, Yadav was the lone Governor who completed his full term after the BJP-led NDA Government came to power at the Centre in May 2014.