It happened around 12:30 Saturday morning at The Easy Corner Bar on the 500 block of North 35th Street.
Officials say two men were involved in the dispute and shots were fired while dozens of patrons were inside.
Police arrived on the scene and found a man in his 20s suffering from multiple gunshot wounds.
The victim was taken to the Hospital of the University of Pennsylvania and was later pronounced dead.
Police are reviewing security cameras from inside the bar.
So far no arrests have been made.