Francisco Javier Solorio Jr., 39, was killed by a shark while surfing at Surf Beach, Lompoc, Santa Barbara County, California, about 240km north of Los Angeles.
He was bitten on his upper torso.
According to press reports a fellow surfer pulled him to shore and tried to resuscitate him, but when paramedics arrived on the scene they pronounced him dead.
The beach is located near Vandenberg Air Force Base, the site of a fatal shark attack in 2010.
The type of shark involved and other details were not immediately available.
The shark is believed to be a 15-16 foot great white.