The shooting at 4100 E. Ocean Blvd. occurred about 2 a.m., said Long Beach Police Department Sgt. Dina Zapalski. Michael Martoni, 36, of Long Beach, a customer at the bar, died at the scene, she said.
A motive for the crime was unknown, Zapalski said.
Martoni was gunned down outside the establishment's back entrance, Zapalski said.
Homicide detectives were investigating the circumstances of the attack, but no immediate arrests were made, she said.
Several Yankee Doodles' employees could be seen weeping at the scene following the shooting.