He is survived by wife and a son and a daughter, both of whom reside abroad.
Mishra was suffering from coronary artery problem for some time. He had asked his domestic help to bring his dinner but was found in an unconscious condition. The security guards were summoned and he was rushed to the hospital.
A career diplomat, Mishra was Principal Secretary to Prime Minister Atal Bihari Vajpayee before he was appointed as the NSA. He had earlier retired as Secretary in the External Affairs Ministry after having served as India's Permanent representative to the UN. He had played a crucial role in assisting Vajpeyee during the Kargil conflict in 1999.
After the fall of the NDA government in 2004 and the fading away of Vajpayee from the political scene, Mishra distanced himself from BJP and often criticised its stand on various foreign policy issues. He also batted for the Indo-US nuclear deal when Prime Minister Manmohan Singh was negotiating with Washington and attacked BJP for opposing it.
In a condolence message, Vice President Mohammad Hamid Ansari described Mishra's death as a "personal loss" to him. Prime Minister Manmohan Singh on Saturday condoled the death of Mishra and said with his passing away, the nation has lost a towering pillar of its strategic community.
Mishra will be cremated Lodhi Road Crematorium at 11 am on Monday, his family sources said.