The woman, Yun Lee, is considered at risk because she possibly suffers from Alzheimer’s disease.
Lee, who only speaks Cantonese, arrived in the United States approximately one month ago to visit her son.
She is known to frequent McClaren Park and San Bruno Avenue between Mansell Street and Silver Avenue.
Lee, who is 5 feet 3 inches tall, weights 100 pounds and has gray hair and brown eyes, was last seen wearing a long-sleeved red shirt, black pants and black shoes.
Anyone who spots Lee is asked to contact San Francisco police at (415) 553-1396.