A judge will need to agree with Gascon's recommendation and then a parole board must approve.
But the Board of Parole Hearings typically schedules hearings no earlier than six months out.
Gov. Gavin Newsom would also have the power to reject the board's decision.
Erik Menendez, now 53, and Lyle Menendez, now 56, are serving life prison terms without the possibility of parole at Richard J. Donovan Correctional Facility in San Diego for the 1989 killings of their parents Jose and Mary Louise "Kitty" Menendez.
Gascón said prosecutors recommended that the brothers' sentence of life without parole be rescinded, and that they be re- sentenced to 50 years to life in prison, with the possibility of parole. Due to their ages at the time of the crime, such a sentence would make them potentially eligible for parole as youthful offenders, even though they have only served about 35 years behind bars.
It will be up to a judge to decide whether to re-sentence the pair. Prosecutors are expected to work with the defense team and the court to have a hearing date scheduled.
If a judge agrees to the re-sentencing proposed by the district attorney's office, the matter would then be in the hands of a state parole board to determine if the brothers are suitable for parole and release from prison. If the board grants parole, the governor could still reject it.
Gascón announced his decision at a Thursday afternoon news conference.
"We are going to recommend to the court (on Friday) that the life without the possibility of parole be removed and they would be sentenced for murder," Gascón said. "I believe that they have paid their debt to society," he said. "The final decision will be made by the judge."
Gascón said part of his decision was based on a review of how the brothers have behaved in prison. Even faced with the likelihood of life in prison, they avoided misbehavior or joining gangs and instead worked to help fellow inmates improve their lives, he said. For example, they worked to create groups to help inmates deal with untreated trauma, and other groups to help inmates with physical disabilities. Lyle also helped advocate for better living conditions for inmates, he said.
The brothers themselves and other family members were not notified of his decision in advance, so likely would have found out the news by watching his televised press conference. He said he finalized the decision only about an hour before the news conference started.
Gascón is currently locked in a battle for re-election against former federal prosecutor Nathan Hochman, who released a written statement questioning the timing of the decision so close to the election:
"D.A. George Gascon received the Menendez habeas corpus petition in May 2023 and request for resentencing in February 2024. Yet, he has waited until days before the November 5 election, 30 points down in the polls with articles coming about how his failed policies have led to additional murders of innocent people, to release his recommendation for resentencing. By releasing it now, Gascon has cast a cloud over the fairness and impartiality of his decision, allowing Angelenos to question whether the decision was correct and just or just another desperate political move by a D.A. running a losing campaign scrambling to grab headlines through a made-for-TV decision. Angelenos and everyone involved deserve better."
During his news conference, Gascón declined to take reporter questions specifically about how the decision relates to his campaign.
But asked what would happen if he loses the election and his successor has a different view of the case, Gascón said it shouldn't make a difference because once his office files their position, the matter is in the court's hands. The DA's office expects to file in court Friday and hopes to get on the court docket in the next 30-45 days. The election is Nov. 5.
Gascón recommends resentencing for Menendez brothers in 1989 killings of their parents
Attorney Mark Geragos, who represents members of the Menendez family supporting the brothers' release, said a detailed plan has been formulated - and shared with the District Attorney's office - for their re-entry into society if they are released. He didn't provide details of the plan for security reasons, but noted both brothers are married to wives who make a living. Both brothers are also enrolled in college programs - Lyle in a master's program and Erik for an undergrad degree.
He remains optimistic they could be home by Thanksgiving.
The family is united behind one idea, Geragos said: "Which is bring 'em home. Bring 'em home. Enough is enough."
The Beverly Hills Police Department, which investigated the 1989 murder, issued a statement which did not praise nor criticize the DA's position, but noted their agency was not involved in the decision.
"Today's decision to recommend resentencing was made entirely by the Los Angeles County District Attorney. BHPD was not consulted or contacted by the District Attorney's Office regarding this decision. As the investigating agency for the case, the BHPD presented relevant facts and evidence to the Los Angeles County District Attorney's Office, which resulted in the filing of criminal charges at that time."
The decades-old case began on Aug. 20, 1989, when Lyle and Erik Menendez fatally shot their parents, Jose and Kitty Menendez, in the family's Beverly Hills home. Lyle Menendez, then 21, and Erik Menendez, then 18, used shotguns they bought days earlier.
Prosecutors alleged the brothers killed their wealthy parents for financial gain.
The defense argued the brothers acted in self-defense after enduring years of sexual abuse by their father.
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Their first trials -- which captured the nation's attention with cameras in the courtroom -- ended in mistrials.
In 1996, at the end of a second trial -- in which the judge barred much of the sex abuse evidence -- the brothers were convicted of first-degree murder and sentenced to two consecutive life prison terms without the possibility of parole.
The sensational case gained new attention this fall with the release of the Netflix drama "Monsters: The Lyle and Erik Menendez Story" and the Netflix documentary "The Menendez Brothers."
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Gascón said this month that his office was evaluating new evidence: allegations from a member of the boy band Menudo who said he was molested by Jose Menendez, and a letter Erik Menendez wrote to a cousin eight months before the murders detailing his alleged abuse.
Erik Menendez's cousin testified about the alleged abuse at trial, but Erik Menendez's letter -- which would have corroborated the cousin's testimony -- wasn't unearthed until several years ago, according to Geragos.
Nearly two dozen of the brothers' relatives united at a news conference last week to push for their resentencing.
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"Their actions, while tragic, were the desperate response of two boys trying to survive the unspeakable cruelty of their father," Kitty Menendez's sister, Joan Andersen VanderMolen, said. "As their aunt, I had no idea of the extent of the abuse they suffered."
"It's time to give them the opportunity to live the rest of their lives free from the shadow of their past," she said.
Behind bars, the siblings "sought to better themselves and serve as a support and inspiration for survivors all over the world," added Jose Menendez's niece, Anamaria Baralt. "Their continued incarceration serves no rehabilitative purpose."
The brothers "deserve a chance to heal, and our family deserves a chance to heal with them," Baralt said.
Despite the massive show of support, one relative -- the brothers' uncle, Milton Andersen -- is adamant about keeping them behind bars. He said in a statement he firmly believes his nephews were not sexually assaulted and were motivated by greed.
ABC News, City News Service and the Associated Press contributed to this report.