A vehicle control system is provided for a vehicle that is steered by steer-by-wire, the system including a battery mounted in the vehicle, a steer-by-wire steering system that turns wheels by an electric motor that is operated by electric power supplied from the battery, a steering controller for controlling the operation of the steer-by-wire steering system, and an engine controller for controlling, by electric power supplied from the battery, the operation of an engine for making the vehicle travel. A booster circuit boosts the voltage applied to the steering controller so that, when the voltage of the battery decreases, the voltage applied to the engine controller falls below its minimum operating voltage before the voltage applied to the steering controller falls below its minimum operating voltage. With this arrangement, it is possible to provide fail-safe operation when there is a decrease in the voltage of the battery which supplies electricity to the steering controller.