Sean Allen O'Dell, 47, was last seen on Friday at 3:30 p.m. in the area of Queen Street West and Ossington Avenue. He was on a one-hour pass from, but never returned to, the Centre for Addiction and Mental Health.
He is described as white, six feet tall, weighing 190 pounds, with short grey/brown hair and brown eyes.
He was last seen wearing a grey track shirt, grey track pants, a beige jacket and dark brown shoes.
Police are concerned for his safety.
Anyone with information is asked to contact police at 416-808-1400 or Crime Stoppers at 416-222-TIPS.