It happened at 5:44 p.m. Monday at the Rite Aid store in the 6700 block of North 5th Street in East Oak Lane.
Police say the man walked into the store, approached a clerk a cash register and demanded money.
As he made the demand, he kept his left hand in his jacket pocket and gestured with it as if he were holding a weapon.
The clerk gave the suspect $357 from the register, and the man fled.
Police have released the following description of the suspect:
White male, 40-50 years old, 6'0" tall, 200 lbs, gray-blue beard, wearing a dark colored "Yankees" baseball cap, black colored flight jacket with a gold zipper, black cargo/military style pants and brown work boots.
Anyone with information about this crime or this suspect is asked to call Detective Revell at the Philadelphia Police Northwest Detective Division, 215-686-3353/3354.