Prosecutors have 30 days to appeal against this decision to the state Supreme Court or initiate a new trial.
At the moment Syed and his lawyers celebrate the victory.
"He's happy, he's very happy," attorney C. Justin Brown told CNN. "He waited 18 years to hear that."
The Attorney General's office in Maryland, which could appeal, "reviews today's decision to determine next steps," spokeswoman Raquel Coombs said.
The Long and Winding Road
Syed, 36, served a life sentence in the murder of his ex-girlfriend Hae Min Lee. Her strangled body was found in a shallow grave in a park a month after her release in January 1
Prosecutors relied on statements from their friend Jay Wilds, who helped Syed dig a hole for Lee's body. To substantiate his report, the prosecution filed cell phone records and testimonies to place Syed in the place where Lee was buried.
He was convicted in 2000 and sentenced to life imprisonment for murder and kidnapping.
The state appealed the 2016 Order, which led to the court's ruling on special appointments on Thursday.
Brown is optimistic that they will get a new trial. He said he hopes the state will refrain from appealing and try to try the case again.
"If we go to court, we will win this process," Brown told CNN.
Asked whether Syed will be released on bail before a new trial, Brown told CNN, "It's something we'd consider."
The first season of the "Serial" podcast, consisting of 12 episodes about the case, was downloaded more than 40 million times in 2014.
The podcast dug into a trail that would give Syed an alibi.
Prior to his trial, Syed gave his lawyers two letters from Asia McClain, a classmate who said she saw Syed in a library around the time of the murder.
Your account did not make it into the defense case, leading (19659002) The judge of the hearing after the conviction agreed with Syed, and the prosecutor appealed.
In the decision of Thursday, two judges of the appeals court agreed with the merits, the opposing lawyer claims that there are times when lawyers have good reasons not to contact a potential alibi witness.
Syed's litigation attorney, M. Cristina Gutierrez, died before being convicted.
 CNN's Marlena Baldacci and Emanuella Grinberg have contributed to this report.