The gunman entered the shoe store in the 1200 block of North Lake Avenue about 7 p.m. on Saturday, brandishing a handgun and demanding money.
A female clerk handed over at least $100 and the robber fled on foot. There were no reports of any injuries that might have taken place, during the course of the robbery.
The suspect was described as a white or Latino man, about 6 feet tall, with a thin build and wearing dark clothing.
Pasadena police detectives asked anyone with any information regarding the suspect or the robbery to call them at (626) 744-4501.