The panel acted Wednesday after a parole hearing.
Manson, now a gray-bearded, 77-year-old, did not attend the hearing.
He orchestrated a series of gruesome murders on consecutive nights in Los Angeles 40 years ago. His trial with three women acolytes was an international spectacle.
Manson and his followers were convicted in the 1969 slaying of actress Sharon Tate and four others.
"I'm done with him," Debra Tate, the sister of the actress, said after the hearing.
For four decades, Debra Tate has traveled to whatever rural California prison has held the notorious cult leader and his band of murderous followers for hearings she said are too numerous to count.
"I've tried to take this thing that I do, that has become my lot in life, and make it have purpose," the 59-year-old Tate said Tuesday. She was 17 in August 1969, when Manson sent his minions across LA on two nights of terror.
"I've been doing it for Sharon and the other victims of him for the last 40 years," she said.
The parole board ruled that Manson had shown no efforts to rehabilitate himself.
"This panel can find nothing good as far as suitability factors go," said John Peck, a member of the panel.
The hearing at Corcoran State Prison in Central California could be the last one for the aging mass murderer.
Under current law, inmates can be denied the chance to reapply for parole for up to 15 years. Another rejection could make Manson 92 before he would get another opportunity to make his case.
"At his age, I think he doesn't care," Deputy District Attorney Patrick Sequeira has said. "He would be lost if he got out. He's completely institutionalized."
Manson has not appeared at a parole hearing since 1997. His most recent hearing was in 2007.
Manson, however, is anything but a recluse. He has a steady stream of visitors who submit requests to see him, including college students writing papers about him, said Theresa Cisneros, spokeswoman for Corcoran State Prison.
Manson must approve all requests.
"He has a large interested public," Cisneros said, adding that Manson receives more mail than most prisoners.
Manson has been cited twice for having smuggled cellphones. Authorities found he had been talking with people in California, New Jersey, Florida, British Columbia, Arkansas, Massachusetts and Indiana.
The phone numbers were traced, but Department of Corrections spokeswoman Terry Thornton said she could not disclose who received the calls.
Manson also was cited in October for having a homemade weapon in his cell.
Manson was depicted at trial as the evil master of murder, commanding a small army of young followers. He and the three women were sentenced to death. But their lives were spared when the California Supreme Court briefly outlawed the death penalty in 1972.
One of them, Susan Atkins, died in prison. Two others, Leslie Van Houten and Patricia Krenwinkel, remain incarcerated.
Manson also was convicted of two unrelated murders.
The Associated Press contributed to this report