A cab driver flagged down Officer Pasquale Carpentiere around 11:30 p.m. and told him his passenger was in labor.
Carpentiere called for an ambulance but the baby couldn't wait, so Carpentiere delivered the 7 1/2-pound baby in the cab.
Officers Jorge Negron and Agostinho Matias arrived shortly afterward to help. Matias is a registered nurse.
The mother and child were taken to Bellevue Hospital and are doing well.
The mother was identified as 39-year-old Alertime Antoncik of the Bronx.