Los Angeles County Sheriff's Department deputies were called around 1 a.m. to the King Bar at 2822 E. Avenue I for a shooting report.
They found two people, a man and a woman, with gunshot wounds. Both were transported to a local hospital, where the man underwent surgery in critical condition. An update on the woman's condition was not immediately available.
The shooting happened in the bar's parking lot and two suspects, a man and a woman, fled in a white Toyota Corolla.
A motive for the shooting was under investigation.
Authorities had been called to the same bar a short time earlier on a report of customers fighting and getting kicked out of the bar.
LASD's Operation Safe Streets Bureau, which investigates criminal street gangs, is handling the case.