The Fashion Police star's daughter Melissa announced the sad news this evening (4 September) in a statement, before thanking the doctors and nurses who had been caring for her.
Melissa, who starred alongside her mother in reality TV show Joan & Melissa: Joan Knows Best, said: "She passed peacefully at 1:17 p.m. surrounded by family and close friends.
"My son [Cooper] and I would like to thank the doctors, nurses, and staff of Mount Sinai Hospital for the amazing care they provided for my mother."
She added: "Cooper and I have found ourselves humbled by the outpouring of love, support, 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 right now, I know her final wish would be that we return to laughing soon."
Joan's death comes a week after the iconic star suffered a cardiac arrest during a routine throat operation in New York. Six days later, Melissa confirmed that her mother had been placed on life support.
Up until her operation, Joan had been working hard working TV show Fashion Police, covering events such as the MTV Video Music Awards and the Emmys alongside her co-stars, including Kelly Osbourne.
Joan has been a prominent figure in the US entertainment industry since rising to fame in 1965 following an appearance on the Tonight show.
Tonight, tributes for the star have begun pouring in on Twitter. Ellen Degeneres tweeted: "Joan Rivers will always be a pioneer. She paved the way for a lot of comedians. I'm very sad she's gone."
Ultimo founder Michelle Mone said: "How sad #RIPJoanRivers Head strong, entrepreneur, direct, offensive, extremely talented & funny."
Referencing Joan's comic side, Piers Morgan meanwhile told his followers: "Joan Rivers wouldn't want saccharine tributes tonight. She'd want people taking the piss."
Kelly Osbourne is yet to make a public tribute. Her mother Sharon said: "We've lost a true legend today and an amazing woman - a pioneer.
"She opened up the arena for women in comedy. My heart goes out to Melissa & her son Edgar Cooper. Love and respect from the Osbourne family to you both."