Stanley Gentry was last seen around 8:30 am walking in his neighborhood near Shields and Maple in central Fresno.
The Fresno County Sheriff's Office says Gentry has Schizophrenia and needs his medication immediately.
He is six-foot-four and 230 pounds with green eyes and gray hair.
Anyone with information is asked to contact the Fresno County Sheriff's Office at 559-600-3111.