Dandenong man Daniel Warren is missing.
Police said the 22-year-old was last seen at a hospital on David Street about 4pm on Monday 29 August.
They have concerns for his welfare, as he suffers from a medical condition.
Daniel is Caucasian and about 185 centimetres tall, with a slim build.
He was last seen wearing a green jumper, black tracksuit pants and an orange baseball cap.
Police urged anyone who saw Daniel to call Dandenong Police Station on 9767 7444.