It happened at 12:30 am Thursday when an officer spotted a suspicious white car heading west on McKinley Avenue near Chestnut.
Officers followed, but near Highway 168, the officer collided with another car.
One officer was taken to the hospital. The other officer is okay.
The driver of the other car is also okay and helping with the investigation.
The driver of the white car is still on the loose.
Police have not released a description at this time.
Anyone with information is asked to call Fresno police.