Williams, 84, had been battling bladder cancer.
Williams' publicist, Paul Shefrin, told KARK 4 News sister station KOLR10 News in Springfield, Missouri, that Williams passed away at his home in Branson.
Williams was perhaps known best for his song "Moon River," from the movie "Breakfast at Tiffany's." The song won an Academy Award. He had 18 gold, and three platinum albums in his 75-year career.
He was also a successful television host in the 1960's and 70's. He brought his show to Branson, Missouri in 1992, building the Moon River Theatre, and was known nationally for his live Christmas shows, which were reminiscent of his Christmas shows on television in the 60's.
Last November, Williams told his theater audience he was diagnosed with bladder cancer.
He is survived by his wife, Debbie, and three children.
Publicist Paul Shefrin issued this statement:
"Legendary singer Andy Williams passed away last night (Tuesday) at home in Branson, Missouri following a year long battle with bladder cancer, it was announced by his family. Williams, 84, who also had a residence in La Quinta, California, is survived by his wife Debbie and his three children, Robert, Noelle and Christian. In lieu of flowers, the family asks that donations be made to the Bladder Cancer Advocacy Network. For information go to http://www.bcan.org."
See more on Williams in his biography, attached below.