The two-vehicle crash happened just after 9 p.m. in the 7900 block of Delridge Way SW.
Police say a Honda CRV was making a left turn from SW Kenyon Street onto Delridge Way when it was hit by a Chevy pickup truck.
The Chevy flipped on impact, killing a man who was riding in the bed of the truck, according to police.
The Honda driver, a man in his 50s, had no signs of impairment and was sent to Harborview Medical Center with non life threatening injuries. The Chevy driver, who did show signs of impairment, was also taken to Harborview, but is expected to fine.
When he's released from the hospital, the man will be booked into King County Jail for investigation of vehicular homicide, according to police.
Traffic Collision Investigation Squad detectives responded to the scene and continue to actively investigate.