The incident happened early Friday morning at JJ's Lounge on the 200 block of West Duncannon Avenue.
Click here to watch the surveillance video
Police say the robbers walked into the bar at 12:30 a m. armed with a handgun and demanded cash from the register.
They stole an unknown amount of money and emptied the tip bucket into a plastic bag.
Next, one of the suspects hit a patron in the back of the head with his gun and demanded everyone inside to get on the floor before robbing several customers of their cell phones and wallets.
The pair then fled the scene south on 2nd Street.
Police describe the first suspect as a black male in his early to mid 20s, 5'8" tall and 140 lbs. He was wearing a black hooded sweatshirt, blue jeans, black boots, black ski mask, and black gloves.
The second suspect is described as a black male in his early to mid 20s, 5'11" tall and 160 lbs. He was wearing a black hooded jacket, blue jeans, white sneakers, black ski mask, and black gloves.
Anyone with information is asked to call police at 215.686.TIPS (8477) or text a tip to PPD TIP or 773847.