Officers and medics responded to the scene, a residence in the 100 block of 29th Avenue, at about 6:30 a.m. after receiving a report of an assault with a knife, said Seattle police spokeswoman Renee Witt.
The victim told police that his 53-year-old girlfriend had stabbed him in the head with a knife and then fled the scene in her vehicle.
Seattle Fire Department medics treated the man, who sustained 2- to 3-inch lacerations to the left rear side of his head.
The man refused to provide a statement or tell officers what precipitated the assault.
The girlfriend was last seen leaving the area in her vehicle, a black 2000 Ford Taurus 4-door.