The TV presenter suffered a cardiac arrest at the end of last month, and on 2 September her daughter Melissa revealed she had been placed on life support.
Yesterday, Melissa said that her mother had been taken out of intensive care. But this evening she released a statement with the tragic news.
She said: "It is with great sadness that I announce the death of my mother, Joan Rivers. She passed peacefully at 1.17pm surrounded by family and close friends.
"My son and I would like to thank the doctors, nurses and staff of Mount Sinai Hospital for the amazing care they provided for my mother.
Melissa continued that she and her son Cooper "have found ourselves humbled by the outpouring love and prayers we have received from around the world. They have been heard and appreciated.
"My mother's greatest joy in life was to make people laugh. Although that is difficult to do now, I know her final wish would be that we return to laughing soon."
An actress, comic and author, Joan was perhaps more recently best known for her celebrity style show Fashion Police, on which she discussed candidly the best and worst dressed stars.
Speaking once of her work, Joan said: "What pleasure you feel when you've kept people happy for an hour and a half.
"They've forgotten their troubles. It's great. There's nothing like it in the world. When everybody's laughing, it's a party."