The incident happened around 7 p.m. at the Exxon Station on the 4200 block of Whitaker Avenue.
Police say four armed masked men were casing the station.
There were gambling machines reportedly located inside the business.
As an employee began taking money out of a safe, the robbers struck, officials say.
The robbers reportedly took about $25,000.
There are no reports of any injuries at this time.
Anyone with any information is asked to call police at 215-686-TIPS.