The former Manson Family leader, now 83, was hospitalized in Bakersfield, California, three days ago, TMZ first reported Wednesday.
Manson is one of the famous criminal the America, and has been caged for more than four decades after the killing spree in August 1969 that resulted in the deaths of seven people including Tate, the then-wife of film director Roman Polanski. Prosecutors said Manson and his followers were trying to incite a race war he dubbed "Helter Skelter", taken from the Beatles song of the same name.
The next night, Watson and two female cult members tied up and stabbed Leon and Rosemary LaBianca to death in their Los Angeles home.
He was sentenced to death, a sentence which was later amended to life imprisonment in Corcoran State Prison after California discontinued the death penalty.
At his last parole hearing in 2012, the parole board described Manson as unhinged and remorseless and denied him permission to reapply for release until 2027, when he would be 92 years old.
It's unclear at which hospital Manson is being treated. A spokeswoman for the hospital declined to comment.