The man was stabbed and his injuries were reported to be life-threatening. The woman sustained facial injuries that were less serious.
Deputies and medics responded to the scene, in the 21800 block of 167th Street Court East, at about 12:30 p.m. after receiving a report of a stabbing.
Arriving at the scene, in a small housing development, they found the injured man and woman. They were treated then taken to the hospital, said Teresa McCallion of East Pierce Fire and Rescue.
Officials said the assault appeared to be "mutual."
The Pierce County Sheriff's Department is investigating.