Police say the two men walked into the New Almonte Mini Market on the 2000 block of West Spencer Street just before 9 p.m.
They pointed handguns at the clerk behind the counter and demanded cash.
The gunmen got away with $300 from the registers before fleeing the scene.
They were last spotted heading west on Spencer Street and then north on Woodstock Street.
No injuries were reported.
The first suspect is described as a black male, 6'0" tall with a stocky build. He was wearing a thick black jacket, black pants, dark colored ski mask, gray/black work gloves, and armed with handgun.
The second suspect is described as a black male, 6'0" tall with a stocky build and light complexion. He was wearing a gray flannel shirt, dark colored hooded sweatshirt, dark colored pants, maroon "New Balance" sneakers, and armed with a handgun.
If you recognize these suspects, call police at 215.686.TIPS (8477) or text a tip to PPD TIP (773847).
VIDEO: Click here to watch the surveillance video