Police are looking for a 24-year-old Hilton man who went missing on May 11.
David John Houston was dropped off in a taxi near Redmond Road in Coolbellup about 7pm.
A police spokeswoman said he has not had contact with his family and friends since then, which is out of character.
Mr Houston was described as Caucasian and 180cm tall with a medium build, brown eyes and long, straight brown hair, which is usually tied in a pony tail.
He was last seen wearing dark-blue jeans, a white long-sleeved button up shirt and white runners.
Police and his family have serious concerns for his welfare.
If you have any information regarding Mr Houston please call police on 131 444 or Crime Stoppers on 1800 333 000.