The 3-pound boy was taken to Jersey City Medical Center. Doctors say he was born 11 weeks early, but that his vital signs are stable.
Investigators will be looking at surveillance footage near where the baby was found to see if they can spot the person leaving the bag there.
15-year-old Keyshaun Wiggins and his friends found the newborn in a plastic Pathmark bag and immediately went to get the building's super, who called 911.
"The baby could have suffocated in the bag," said Wiggins. "We heard something crying in the bag, we thought it was an animal or something. So we went up to the bag, and we saw the baby's hand coming."
Rebecca Wolmers is the super's wife. She says she and her husband rushed towards the spot where the teens found the child, and what she saw frightened her.
"I opened the bag and made a hole, and saw the baby and it had a lot of tissue around it," Wolmers said.
It is no way for a person's life to start, but the child has beaten the odds, thanks to some Good Samaritans.
"I feel proud of myself," adds Wolmers.
The super's wife tells Eyewitness News that no one in the building was pregnant.
In New Jersey, the Safe Haven Law allows a person to drop off a baby at a manned police or fire station, or at a hospital and not be prosecuted. The law was designed and created to protect children, and avoid situations like this.
For more about the New Jersey Safe Haven Law, CLICK HERE.