A battery management system for a vehicle is provided to prevent current consumption of a battery by operating a relay connected between the battery and electronic loads to prevent an over-discharge of the battery. The battery management system includes a sensing unit that is configured to measure a current and a voltage of a battery for a vehicle and a relay that is connected between the battery for the vehicle and electronic units of the vehicle. Additionally, a controller is configured to receive data from the sensing unit to turn off the relay.