Dikshit was unwell for some time and was admitted to a private hospital.
Dikshit served as the chief minister of Delhi for three terms from 1998 to 2013. She was the longest serving chief minister of Delhi.
In the recently concluded Lok Sabha polls, under her leadership, the Congress party managed to push AAP candidates on the third place in five of the seven seats in Delhi, besides registering growth in its vote share.
In January this year, the three-time former Delhi chief minister was appointed president of the city unit after the incumbent Ajay Maken stepped down citing health issues.
Despite being an octagenarian, Dikshit led the party in Lok Sabha polls and herself contested against Delhi BJP chief Manoj Tiwari from the North East Delhi seat. She lost by over 3.66 lakh votes.
President Ram Nath Kovind extended his condolences to the family of the Congress leader and said that her term was a period of momentous transformation for the capital.
Prime Minister Narendra Modi was one of the first political leaders to extend his condolences.
Congress leader Rahul Gandhi said that the party has lost a beloved daughter.
Delhi chief minister Arvind Kejriwal termed the demise of Dikshit a huge loss for the city.