Police released surveillance video from the store at 917 Filbert late Thursday night.
The clerk told police the man walked in, pulled out a handgun and told him, "You know what this is, give me all the money."
The suspect then cleared out the cash drawer, grabbed five packs of cigarettes, and ran.
The clerk wasn't hurt
Watch the surveillance video on the Philadelphia Police Department's YouTube page.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.