The shooting happened shortly before 3 p.m. Friday in the 15700 block of Saticoy Street.
According to a friend of the victim, the business owner caught someone spray painting graffiti on his shop. He told the suspect to stop tagging and walked inside, but the suspect followed and shot the business owner.
The unidentified victim was transported to a nearby hospital, where he died.
Los Angeles police said the suspect immediately fled the scene and was at large.