It happened Monday afternoon in the Soundview section.
Officer Jose Vargas was in a police van when someone knocked on the door, telling him a 14-mont-old baby, Genesis Lopez, was unconscious and not breathing in a nearby car.
Vargas called for backup and started CPR with his supervisor, Lt. Joussett DeJesus.
Within minutes, Sgt. Rogelio Pagan arrived and took over the CPR.
"The baby's eyes were rolled back, the baby was looking up to the sky and her mouth was open. I immediately grabbed the baby from the female, I flipped the baby over onto her stomach and I placed her in a downward position, securing the baby on my waist, and I struck the baby twice in the back," Sgt. Pagan said.
"I want to thank them, they were so nice, and thanks a lot for helping my daughter," said Noelia Torres, Genesis' mother.
Genesis was released from the hospital Monday night after spending a few hours under observation.