Theodore Walker, 82, was last seen leaving Bronx Lebanon Hospital in the Bronx on Friday around 6:30 pm.
At the time of his disappearance, he was wearing a black shirt, brown pants and brown slippers.
Walker stands 6-feet-tall and is approximately 140 pounds.
He is in poor mental health and requires medical assistance.
Anyone with information in regards to his whereabouts is asked to call the NYPD's Crime Stoppers Hotline at 800-577-TIPS or text their tips to 274637(CRIMES).