Spector died from complications after contracting Covid-19, according to reports.
He was serving a 19 years-to-life sentence for the 2003 murder of Hollywood actress Lana Clarkson.
Spector, who changed the sound of pop music in the 1960s with his "Wall of Sound" recordings , had been diagnosed with Covid-19 four weeks ago and was transferred from his prison cell to a hospital, it has been reported.
The California Department of Corrections and Rehabilitation said on Sunday he had died of natural causes in hospital .
Spector produced 20 top 40 hits between 1961 and 1965 and went on to work with the Beatles, the Righteous Brothers and Ike and Tina Turner. He also influenced artists ranging from the Beach Boys to Bruce Springsteen, who emulated the Spector sound on his classic single "Born to Run."
He was disgraced after his conviction for murder.
In its statement the California Department of Corrections and Rehabilitation said: "California Health Care Facility inmate Phillip Spector was pronounced deceased of natural causes at 6.35pm on Saturday, January 16, 2021, at an outside hospital.
"His official cause of death will be determined by the medical examiner in the San Joaquin County Sheriff's Office.
"Spector was admitted from Los Angeles County on June 5, 2009, for second-degree murder. He had been sentenced to 19 years to life for the shooting death of actress Lana Clarkson.
"Before his incarceration, Spector was an influential record producer, musician and songwriter best known for developing a music production technique called the 'wall of sound'."
Spector was convicted of murdering actress Lana Clarkson in 2003 at his castle-like mansion on the edge of Los Angeles. After a trial in 2009, he was sentenced to 19 years to life.
Clarkson, star of "Barbarian Queen" and other B-movies, was found shot to death in the foyer of Spector's mansion in the hills overlooking Alhambra, a modest suburban town on the edge of Los Angeles.
Until the actress' death, which Spector maintained was an "accidental suicide," few residents even knew the mansion belonged to the reclusive producer, who spent his remaining years in a prison hospital east of Stockton.