Earlier in the day, 57-year-old Kavita had slipped into coma.
"Her condition turned critical and she lapsed into a coma soon afterwards. She did not recover and was declared brain-dead", a hospital spokesperson said.
Kavita is survived by two daughters Jui and Sayali and son Akash.
The family has consented to donate her organs including kidneys, liver, eyes and skin, hospital sources said.
[Also read: Kavita Karkare slips into coma]
In 2008, Hemant Karkare had sacrificed his life while fighting terrorists during the 26/11 attacks in Mumbai.
He was killed on the night of 26/11 near Cama Hospital, along with Additional Police Commissioner Ashok Kamte and senior police inspector Vijay Salaskar.
After his death, Kavita was in the limelight for demanding better weaponry, training and other facilities for the police personnel engaged in life-threatening situations.