Roy Thompson was last seen Friday morning in West Seattle, but deputies say the 81-year-old was last seen at his Renton home on Thursday.
Thompson has serious medical issues that need to be addressed, according to deputies.
Since he left home, Thompson has been as far away as Stanwood, and he was spotted in Burien prior to that. He used to live in Kent, so he's familiar with the area, according to deputies.
Thompson stands 6 feet tall and weighs roughly 155 pounds. He has blue eyes and gray hair. He wears eye glasses and was last seen wearing tan clothes.
Thompson drives a gray 2006 Toyota Avalon with Washington license plates AJY8994.
Anyone with information about Thompson's whereabouts is asked to call the King County Sheriff's Office 911 Center at 206-296-3311.