Police say two officers were contacted by paramedics at about 1:20 a.m. after a woman went into labour inside a cab in the city's east end.
Paramedics were on their way to the call, but the officers arrived on the scene first.
Police say one of the officers coached the mother through the delivery while the other held the baby.
Paramedics arrived after the birth and took the mother and the baby boy to hospital.