Police say the officer was responding to another car accident just before 2 p.m. when the crash happened.
The officer was driving northbound on Fairview Avenue North with his siren activated when a large truck pulled out of the Fred Hutchinson Cancer Research Center's driveway and hit the car.
The collision forced the patrol car onto a planting strip, where it came to a stop, according to police.
The officer, who has not been identified, was taken to Harborview Medical Center with undisclosed but non life-threatening injures.
The patrol car was towed away. The truck driver wasn't cited, which police say is standard procedure in car wrecks that require extensive follow-up investigations.
The department's Traffic Collision Investigation Squad is investigating.