Police were called to the shoe store, located at 1310 El Camino Real, at about 8:30 p.m. to respond to a report of a robbery.
An employee at the store told officers that a man wearing a ski mask, a dark hooded jacket and jeans had walked into the store and demanded money.
The man then fled the store with an undisclosed amount of cash, police said.
Officers searched the area but didn't find the robber, who is believed to be about 5 feet 8 inches tall and weigh about 200 pounds. His race is unknown, police said.
Anyone with information about the case is asked to call San Bruno police at (650) 616-7100.