The shooting happened in an alley on the 1300 block of North Lawrence Avenue at about 6 p.m. Saturday.
The man was taken to Anaheim Regional Medical Center and treated for a gunshot wound to the chest. He was pronounced dead after being transferred to UC Irvine Medical Center.
The man's identity was not immediately released, but police are asking for any information the public might have about the shooting.
If you have any information regarding this incident, you're urged to contact police at (714) 765-1944.