The accident happened on St. Clair Avenue West near Old Weston Road at about 2 a.m.
Police say a blue Nissan travelling westbound mounted the curb and struck the pole.
The impact totalled the car and sent the debris flying.
There were three people in the Nissan and two in the police car, which was stopped nearby.
The driver of the Nissan was taken to hospital in serious condition.
The two passengers and the two police officers received only minor injuries.
No names have been released.