Philin Phen was last seen around noon on Thursday in the McCowan Avenue and Sheppard Avenue East area of Scarborough.
Phen wears a Medic Alert bracelet and police said they are concerned for his safety.
He is described as five-feet, four-inches tall, 125 pounds and bald with a thin build. He was last seen wearing a Maple Leafs hoodie, light blue pants, a toque and black Crocs.
Anyone with potentially helpful information is asked to call police at 416-808-4200 or leave a tip anonymously with Crime Stoppers.
Police said Friday morning that they will provide an update on Phen's condition at 10 a.m., but is it not yet clear what information police will provide.