David Boston, 63, was last seen around 9 a.m. in the 9500 block of South Prairie Avenue, according to a CPD missing person alert.
Boston is 6 feet tall and weighs 200 pounds with brown eyes and black hair.
He was last seen wearing a black wool coat, a khaki shirt with a University of Illinois logo, a beige cap and blue jeans with gray shoes, police said.
Boston suffers from dementia and short-term memory loss.
He is known to frequent the 95th Street Red Line Station and the University of Illinois at Chicago campus.
If anyone has knowledge of his whereabouts, they are asked to contact Chicago police at (312) 747-8274.