Silvestre de la Toba was killed while driving with his family when attackers with assault rifles intercepted them and opened fire, AFP reported.
De la Toba's son also died while he wife and daughter were wounded.
Baja California Sur, a northwest state which is a major tourist draw, is saddled by a wave of violence linked to organized crime.
Some 190,000 people have died in drug related violence since 2006 when the government called in the military to fight powerful drug cartels.