Detectives say the gunman could be responsible for a rash of recent robberies in the area.
The latest holdup took place about 11:30 p.m. at the Cobbs Creek Inn on the 6200 block of Catherine Street.
One man emptied the register while the other man took cash and cell phones from the customers.
Police described the gunman as a black man with light complexion, standing 5'8" tall, weighing 300 pounds. He was wearing a dark colored sweatshirt, sunglasses and a cloth covering part of his face.
Investigators think he may be the same man who has robbed three other bars in the last month.
Police say this robbery was a little different than the others, in that the gunman did not act alone, and he made sure to clean out the register.
Surveillance video from early September shows a man aiming his shotgun as he enters the Good Times Bar on the 5500 block of Landsdowne Avenue.
He can be heard asking patrons to empty their pockets.
He then thanks them, and jumps into a white van and speeds off.
Police are concerned that the robberies have become more frequent, and that a future encounter may end up with someone getting hurt.