Abu-Jamal has always maintained his innocence
Judge William Yohn ruled that Abu-Jamal was entitled to a new sentencing hearing for the killing of a Philadelphia police officer in 1981, but he denied him the right to a new trial.
Mr Yohn, citing errors in the original penalty phase of the murder trial, ruled that the new hearing should take place within 180 days, or else Abu-Jamal would automatically be sentenced to life imprisonment instead.
Abu-Jamal is America's most famous death-row inmate - his case has been supported by many Hollywood celebrities and European figures who regard him as a political prisoner of a racist justice system.
His opponents however, see him as an unrepentant murderer.
'Running away'
Abu-Jamal was convicted of killing Philadelphia police officer Daniel Faulkner during a shoot-out in the early hours of 9 December 1981, after the officer pulled over Abu-Jamal's brother for driving the wrong way down a one-way street.
Abu-Jamal, who was wounded in the chest, denies killing the officer and maintains that he was shot whilst running away.
With backing from his network of supporters, Abu-Jamal has launched numerous legal appeals to stall his execution.
New evidence
He exhausted the state appeals process two years ago, but a new petition filed in September argued that the defence had new evidence to clear him, including a confession by a man named Arnold Beverly.
In a 1999 affidavit, Mr Beverly claimed he was hired by the mob to kill Faulkner because the officer had interfered with mob payoffs to police.
However, Abu-Jamal's former lawyers said they thought the confession was not credible and Mr Yohn refused to order Mr Beverly to testify on Abu-Jamal's behalf.