Publicist Maureen O'Connor says Cole died Thursday night. She was 65. O'Connor had no details about how or where Cole died.
Cole had battled drug problems and hepatitis that forced her to undergo a kidney transplant in May 2009.
Cole's 1991 album, "Unforgettable ... With Love," sold some 14 million copies and won six Grammys. It featured reworked versions of some of her father's best-known songs.
On the title cut, "Unforgettable," she sang along with her father's taped version to create a memorable duet. Nat "King" Cole died of lung cancer in 1965.