The murder happened about 3:50 a.m. in front of Tonic on Seventh Avenue near West 48th Street.
The 27-year-old victim had just left the bar when he got into a fight with another man, police said.
The suspect then pulled out a gun and shot the victim in the head.
The victim was rushed to Bellevue Hospital, where he died.
The gunman is still on the loose. Police said the two men appear to know each other.