The woman had just gotten off of a bus at the corner of Linden and California avenues at about 7 p.m. when the suspect forcibly grabbed her purse and ran off, according to South San Francisco police.
The victim was not injured in the robbery, police said.
The suspect was described as a black man in his mid-30s with an average build and height, police said. He was wearing a black hoodie with the hood pulled over his head.
Anyone who might have witnessed the crime is asked to call the South San Francisco Police Department at (650) 877-8900 or the anonymous tip line at (650) 952-2244.