Officers responded shortly after 9 p.m. to a report of a fight in the 14500 block of Crenshaw Boulevard, according to Lt. Steve Pendergast of the Gardena Police Department.
Whether the stabbings happened inside or just outside a barber shop was unclear, police said, adding that blood was discovered in front of and behind the business.
The stabbing victims were transported to Harbor-UCLA Medical Center.
One of the patients was pronounced dead at 10:40 p.m., said Lt. Dave Smith of the Los Angeles County coroner's office. The deceased man's name was not immediately released, pending notification of his family.
The conditions of the three other individuals were unknown.
No arrests have been made in connection with the incident.
Anyone with information about the attacks is asked to call Gardena police at (310) 217-9653.
City News Service contributed to this report.