The drivers collided at Fort Hamilton Parkway and 51st Street in Borough Park just before 9 p.m.
There are reports the ambulance ran a red light on Fort Hamilton Parkway, hitting the bus, which was traveling along 51st Street.
Two EMS workers and the driver of the bus were taken to a local hospital in serious condition.
The 16 children on the bus suffered only minor injuries.
They were checked at the hospital and released.
