Manson ordered his followers to murder actress Sharon Tate and six others in 1969.
Former cult leader Charles Manson has died aged 83.
The news was confirmed by prison authorities in California, who said the former cult leader died of natural causes.
He had been taken to hospital last week in a serious condition, according to US media.
He became one of America's most infamous criminals after ordering his followers to murder actress Sharon Tate and six others in 1969.
Manson - who had a swastika tatooed on his forehead - had instructed female followers to kill in a bid to initiate a race war.
In 1971, Manson and two of his followers were found guilty of seven counts of first-degree murder and one count of conspiracy to commit murder over the August 1969 deaths of Mrs Tate (who was eight months pregnant), Abigail Ann Folger, Wojciech Frykowski, Steven Earl Parent, Jay Sebring, Leno La Bianca and Rosemary La Bianca.
While he was originally sentenced to death, that was changed to life in prison after California outlawed the death penalty.
He ultimately spent more than 45 years in prison.
Manson had been denied parole 12 times, most recently in 2012.
In a statement confirming Manson's death, prison officials said: "Inmate Manson had been housed in the Protective Housing Unit at California State Prison-Corcoran since 1989.
"The unit houses inmates whose safety would be endangered by general population housing."