And another 14 were re-promoted to their ranks during a ceremony at City Hall.
"I can't express the level of joy that I have right now," said Officer William Colon. "It's my city. I love it. I love being a police officer, and I'm thankful to everyone here that's given me the opportunity to continue to serve my community."
"I've just been going to school," said Officer Regina Cousar, "and I graduated in May so I'm just happy to be back working."
"I feel whole again," said Sergeant Steve Wilson. "But I'm more glad for the guys that got laid off that are coming back because we really need them here at the Police Department."
The officers reaffirming their oaths were among the 105 let go last September, about a third of the force. The officers are being rehired with the help of a federal Community Oriented Policing Services (COPS) grant.
After a year out of uniform, these officers are eager to get back to work.
"Doing something you love, and once that's taken away from you it's a void there," said Officer Christopher Munn. "So being that we're able to do what we love again feels good."
"Some of the guys are tired," said Sergeant Mark Kiefer of the Superior Officer Association. "You know, we need the young legs coming back. We're tired. We put in a whole year fighting with just 199 guys. Now you bring in 15, we can share the workload a little bit."
With fewer cops on the street, murders and other violent crime in Trenton has increased. Police Director Ralph Rivera says the rehires and promotions will help fight that.
"Every boot we can get back on the ground is going to be key in assisting us in combating the violence we're facing," he said.
The police director says he will announce plans soon to restructure the department, a move he says will bring it from a good department to a great one.